Anniversary bridge rack reproduction

martin35

AzB Silver Member
Silver Member
Guys

After some discussion with Ssonerai in my ''Anniversary project'' thread, I've decided to start a new thread about bridge rack reproduction build. I'm not ready to start the project yet but I want to get as more information as possible while a wood bending expert is nice enough to share is knowledge.

I'll start with some random ideas to feed the discussion :

- First I will need the original rack dimension
- I'm thinking to use skateboard plywood kit similar to what is sold on that site

https://www.roarockit.ca/skateboard-building/street-deck-maple-7-layer-sets/#.XVNDeehKjcs

-I'll need to find the proper process for the intended shape (Ssonerai should help a lot about that)

Thank you for reading.

Every input is welcome

Thanks

Martin
 
Last edited:

martin35

AzB Silver Member
Silver Member
For reference I've attached a picture from another restoration thread.

CRW_8964.jpg
 
Last edited:

martin35

AzB Silver Member
Silver Member
Contact Mark Gregory....He makes the bridge holders 770-548-4292

Pat

Thank you for the suggestion but I dont want to bother him with my doityourselfer project. If he's willing to share details here it would be great but I'll let him decide if he want spend the time to post something or not.

Also I did not made my home work yet, I can probably still find some information laying around without bothering anybody.

Martin
 

Ssonerai

AzB Silver Member
Silver Member
Martin - If the photo is what you are making, it is a very good item to vacuum bag against a form, from thin layers of veneer or laminae. You should make it oversize and allow for trimming. Whichever side you decide to make the inside curve, will be the area that might give trouble - the veneers have to slide over each other, and they have to slide down into the trough. (Whichever side: often with any sort of press-work, the face is to the form, as that is the most perfect shape and does not change based on thickness of lay-up. OTOH if pressed with the face out from the form, you have to make the form to allow for the thickness of the material. Either way, it can be useful to add some over-bend to allow for springback. A lot of thin layers laid in epoxy will barely spring back, so for gradual curves like yours, it can be made almost net shape. Just don't under-do it.

It could be pressed with a collapsible discharge hose, but that would actually be more complicated.....unless you decide to go into production and make "many". :thumbup:

Is your plan to put the whole thing in a bag? Easiest if you have it, as opposed to sealing an oversized form taping/sealingt membrane on one side.

Will you use a peel layer and a bleeder layer?

I use flag nylon, whatever color is on special since it does not matter, for the peel-ply; and usually just raw burlap for the bleeder.

Besides the purpose for which they are included, they help spread the force of the vacuum over the work and help keep the bag from immediately working into small gaps.
 
Last edited:

martin35

AzB Silver Member
Silver Member
Martin - If the photo is what you are making, it is a perfect item to vacuum bag against a form, from thin layers of veneer or laminae.

It could be pressed with a collapsible discharge hose, but would actually be more complicated.....unless you decide to go into production and make "many". :thumbup:

Is your plan to put the whole thing in a bag? Easiest if you have it, as opposed to sealing an oversized form taping/sealingt membrane on one side.

Will you use a peel layer and a bleeder layer?

I use flag nylon, whatever color is on special since it does not matter, for the peel-ply; and usually just raw burlap for the bleeder.

Besides the purpose for which they are included, they help spread the force of the vacuum over the work and help keep the bag from immediately working into small
gaps.

As I said, my homework is not done yet but from what I've seen I was thinking to put the whole thing in a bag. I think I understand what is the bleeder layer (fluffy material near the vacuum port to let the air bleed) but I have no clue about the peel layer purpose.

Did you look at the material i want to use ? It's 7 ply 1/16 maple veneer kit. I wonder if bending perpendicular to the grain is a problem ? Probably not since the core layers have opposite grain but I'm not sure.

I will also need some advice for the form. I've seen some example made of foam, I dont know if it's really suitable for my application.

Sorry to throw all those questions at you.

Thanks a lot for your advices

Martin
 

Ssonerai

AzB Silver Member
Silver Member
Martin -

Thanks for humoring me, with your kind remarks.

You asked about 2 sided forms, pressing between.
Since that is my current project, i have the most pictures where i actually still know how to find them. Later i will dig out others, with other methods.

These sides were bent in the forms with extra layers of veneer loose to make the total thickness. When the glue set, they were removed, trimmed, and another cross band plus the finish veneer was applied, and back in the forms. You can see that always there is extra margin and extra length, to make the bends go easily. The last pic is the table, but it has only partially been cleaned up. There is also 2 layers of clear packing tape in the coves at each corner to protect the veneers while i was planing and sanding the solid bands down close to flush. The case is now on hold in this partial condition while making the drawers for the other side.

I'll probably get thrown off here for these posts, but will try to get a few more in another day. :sorry:

smt
 

Attachments

  • DSC_0010.jpg
    DSC_0010.jpg
    151.2 KB · Views: 283
  • DSC_0031.jpg
    DSC_0031.jpg
    53 KB · Views: 268
  • DSC_0005.jpg
    DSC_0005.jpg
    150.7 KB · Views: 267
  • DSC_0020.jpg
    DSC_0020.jpg
    94.5 KB · Views: 269
  • DSC_0018.jpg
    DSC_0018.jpg
    136.5 KB · Views: 267

Ssonerai

AzB Silver Member
Silver Member
Martin -
My apologies - I was posting the same time you were, then went out to close up the shop without reading your note immediately above mine.

As I said, my homework is not done yet but from what I've seen I was thinking to put the whole thing in a bag. I think I understand what is the bleeder layer (fluffy material near the vacuum port to let the air bleed) but I have no clue about the peel layer purpose.

The peel ply is so the bleeder and anything else can be stripped easily, if the glue wicks through the top veneers. Or gets smeared on surfaces, as it often does. It is a slick material the glue can wick through, but not stick. The bleeder is so there are no sealed off airbubbles that can't be drawn down by the vacuum. It is a method to let the vacuum permeate thoroughly without restriction. Possibly not necessary on a part the width shown; but also will not hurt.

What happens with only the bag mebrane on a larger assembly, is the bag can seal itself to the surface in areas blocking others off, and no further vacuum can be drawn in them. The diffuser prevents the bag from sealing to the surface of the part. The peel ply prevents a non-synthetic bleeder/diffuser from sticking, as burlap would without the peel layer between it and the part, especially at the edges.

Did you look at the material i want to use ? It's 7 ply 1/16 maple veneer kit. I wonder if bending perpendicular to the grain is a problem ? Probably not since the core layers have opposite grain but I'm not sure.

How wide is your part, and how long? I'm going to have to see what i think bending 7 layers to the inside curve. with half of them being long grain across the S-curve. A perfect vacuum is 14 PSI on most days at sea level, for practical purposes. Depending on your vacuum method perhaps you will net 12 or 13? That's actually quite a lot of pressure, but taking a stack of 1/16" maple veneers 1" wide, and estimating how difficult it is to bend them to the radius is often informative.

Another factor - leverage. If the veneers and form are only exactly the size of the part, it will be difficult to pull the edges down. The form needs to be wider across the bends, so there is leverage on the ends (edges, actually) to force them around the curve. Try pressing 4 layers of long grain tight to the form right up to the ends with your fingers. Then try adding an inch or so, and pressing . Even if the ends still don't go down to the extended radius of the form, they will easily do so further inboard, at the actual part dimension.

I will also need some advice for the form. I've seen some example made of foam, I dont know if it's really suitable for my application.

That is a fascinating and innovative program that guy has developed!
I would be leery of trying 1/16" thick maple cross-laid into the short S-curve shown by your part on a foam form. That said, it never would have occurred to me to try it.:)

How thick is the actual part?

The hollow section of the curve is the difficult area to bend solid and true; all depends on radius and veneer thickness.

smt

PS: If you do try a foam form, it will have to be backed up by a solid flat or the net curve will be a result of the foam curving partially to accommodate the stresses induced in the veneer stack. It will probably curve both widthwise and lengthwise. I find it easier to shape wood than foam, but again, have not actually tried the latter.
 
Last edited:

martin35

AzB Silver Member
Silver Member
Wow SMT it's really impressive work... and thank you to answer all my question.

I dont know the exact measurement of the part yet but it's should be roughly 10'' wide x 30'' long. As for the thickness it will be 1/2'' max ( they also offer 1/22'' thick core board which is giving a 3/8'' th. stack). They also offer birch veneer but it's probably not easier to bend. What kind of wood to you use normally for bending ?

Reading your answer make me think that It can be better to use clamped form as you showed since it probably gives more clamping force but I also understand the dificulty to have a matching set of male and female form taking the thickness of the venner stack into account and still having a good even clamping force...

On the other hand my vaccum pump is not built yet, I have all the component (Vac generator, vac switch, fittings etc..) but I also still have to buy a good size vaccuum bag, which is not cheap...


Anyway I'm not ready to start yet and it will give me time to think abut the whole thing

I greatly appreciate your help.

Thanks again

MArtin
 

Ssonerai

AzB Silver Member
Silver Member
Martin -

Thank you for the nice comments, i just hope i don't get thrown off for sort of non-pool related woodwork. I mean these processes were used for tables and such, but i am not exactly showing that kind of work.

Here are some photos i am relieved to have finally found from a decade ago. Later i will show how some of these parts were vacuum bagged, and some were pressure formed with collapsible discharge hose. If you did not see the finished product first, they will not make sense. So here is the "end" first.
Then i have to go back to work. Try for more tonight. Or during breaks later.

How far up in Quebec are you?
I had to make 3 round trips up to Salaberry-de-Vallefield (below Montreal) earlier in the year.

One comment on your part: If it is literally 10" wide, the 12" wide veneers from that supplier will be "very close" for starting size. They will slip/fan about 1/2" to make the bends, and you need "at least" an inch each side if vac-bagging, plus how accurate can you keep them aligned getting into the form and holding from skewing while the pressure comes down? As said, 12" is about enough, but you need practiced and careful work. Good to try a lay-up like that dry (no glue) and see how you perform under pressure. :wink:. The form will need a balanced shape as well as a hard stop on the downhill side; regardless what is trimmed later, or the layers will try to squirt to one side.
 

Attachments

  • J & M entertainment unit.jpg
    J & M entertainment unit.jpg
    108.6 KB · Views: 288
  • J & M entertainment unit 2.jpg
    J & M entertainment unit 2.jpg
    103.7 KB · Views: 300

Ssonerai

AzB Silver Member
Silver Member
What kind of wood to you use normally for bending ?

I used to bend-laminate a lot of cedar and redwood, for outdoor installations. For cabinet work, most of the common lumber - walnut, maple, birch, rarely pine (i just don't get pine jobs),cherry, poplar, both red & white oak, mahogany are some that come to mind.

Poplar is easy to glue and bend, and does not have much memory or springback. I use mahogany for cores on "important" stuff. It glues well, is stable, and provides rot and generally insect resistance. The curved desk sides above are mahogany, with inner face of birch, outer face is big-leaf maple burl.

Cherry and maple are not ideal in terms of glue saturation - almost similar to some exotics, if you don't sand the faces to about 80 gr and use a wait period for the glue to gel, then apply a fresh batch; it can have starved areas even though pressed down solid. (with epoxy - maple might glue better with titebond, but i never do assemblies that can be rolled and clamped up fast enough to use the fast setting glues like Titebond.) All that work, and then suddenly a mess! WEST with slow hardener gives about 20 minutes to get the parts rolled out, and more than an hour to get them assembled. Keep the shop below 70° and the lay-up time is even longer. You do have to use the cotton flocking ("micro fibers") in the mix, for adequate bond in almost any wood lay-up.

Titebond Extend gives an excellent bond for interior work - so long as you can get everything rolled and fully clamped in 15 minutes or less for bent laminations. I use if only for smallish parts. The other factor is that "yellow" glues put a lot of moisture into the part, so you should not machine it immediately. Let it rest 3 days to a week, depending on thickness and number of layers. (More thin layers = more moisture). I have had some parts bend tighter as they dried, with titebond. Not enough to be a factor for the things we are discussing, though.


I saw all my own veneers. (& laminae)
Here is a post on it from a few years ago.
https://www.practicalmachinist.com/...achinery/another-veneer-resawing-post-303892/

On the project pictured, i did one door with vac, then did another with pressure. Partly as a demonstration. Partly because at the time i was using the pressure system for the larger shelves, and it is just simpler at some level. You might not think so from pics, but it saves all the nuisance of the other plies and the oily vacuum pump running for 6 or 8 hours.
 

Attachments

  • DSCN0007.jpg
    DSCN0007.jpg
    203.7 KB · Views: 229
  • DSCN0011.jpg
    DSCN0011.jpg
    161.9 KB · Views: 229
  • DSCN0014.jpg
    DSCN0014.jpg
    198.1 KB · Views: 229
  • DSCN0013.jpg
    DSCN0013.jpg
    206.7 KB · Views: 234
  • DSCN0015.jpg
    DSCN0015.jpg
    168.9 KB · Views: 229

martin35

AzB Silver Member
Silver Member
Martin -

Thank you for the nice comments, i just hope i don't get thrown off for sort of non-pool related woodwork. I mean these processes were used for tables and such, but i am not exactly showing that kind of work.

Here are some photos i am relieved to have finally found from a decade ago. Later i will show how some of these parts were vacuum bagged, and some were pressure formed with collapsible discharge hose. If you did not see the finished product first, they will not make sense. So here is the "end" first.
Then i have to go back to work. Try for more tonight. Or during breaks later.

How far up in Quebec are you?
I had to make 3 round trips up to Salaberry-de-Vallefield (below Montreal) earlier in the year.

One comment on your part: If it is literally 10" wide, the 12" wide veneers from that supplier will be "very close" for starting size. They will slip/fan about 1/2" to make the bends, and you need "at least" an inch each side if vac-bagging, plus how accurate can you keep them aligned getting into the form and holding from skewing while the pressure comes down? As said, 12" is about enough, but you need practiced and careful work. Good to try a lay-up like that dry (no glue) and see how you perform under pressure. :wink:. The form will need a balanced shape as well as a hard stop on the downhill side; regardless what is trimmed later, or the layers will try to squirt to one side.

I say it again , it's really impressive work. I'm living near Sherbrooke which is 100miles south-east of Montreal near the Vermont border.

As for the dimension of the finish part, I just dont know them exactly , it was only a guess from the picture.

I'm looking forward to see the other processes and thank you again for all the great first hand information and advices.

Martin
 

martin35

AzB Silver Member
Silver Member
I used to bend-laminate a lot of cedar and redwood, for outdoor installations. For cabinet work, most of the common lumber - walnut, maple, birch, rarely pine (i just don't get pine jobs),cherry, poplar, both red & white oak, mahogany are some that come to mind.

Poplar is easy to glue and bend, and does not have much memory or springback. I use mahogany for cores on "important" stuff. It glues well, is stable, and provides rot and generally insect resistance. The curved desk sides above are mahogany, with inner face of birch, outer face is big-leaf maple burl.

Cherry and maple are not ideal in terms of glue saturation - almost similar to some exotics, if you don't sand the faces to about 80 gr and use a wait period for the glue to gel, then apply a fresh batch; it can have starved areas even though pressed down solid. (with epoxy - maple might glue better with titebond, but i never do assemblies that can be rolled and clamped up fast enough to use the fast setting glues like Titebond.) All that work, and then suddenly a mess! WEST with slow hardener gives about 20 minutes to get the parts rolled out, and more than an hour to get them assembled. Keep the shop below 70° and the lay-up time is even longer. You do have to use the cotton flocking ("micro fibers") in the mix, for adequate bond in almost any wood lay-up.

Titebond Extend gives an excellent bond for interior work - so long as you can get everything rolled and fully clamped in 15 minutes or less for bent laminations. I use if only for smallish parts. The other factor is that "yellow" glues put a lot of moisture into the part, so you should not machine it immediately. Let it rest 3 days to a week, depending on thickness and number of layers. (More thin layers = more moisture). I have had some parts bend tighter as they dried, with titebond. Not enough to be a factor for the things we are discussing, though.


I saw all my own veneers. (& laminae)
Here is a post on it from a few years ago.
https://www.practicalmachinist.com/...achinery/another-veneer-resawing-post-303892/

On the project pictured, i did one door with vac, then did another with pressure. Partly as a demonstration. Partly because at the time i was using the pressure system for the larger shelves, and it is just simpler at some level. You might not think so from pics, but it saves all the nuisance of the other plies and the oily vacuum pump running for 6 or 8 hours.


You type faster than me, I've missed your post while I was making mine. I see that you post on Practical Machinist, I use to hang around that forum quite a bit under the same user name some years ago..
Thank you so much, it will take me some time to read and digest all these great infos.

Martin
 
Last edited:

martin35

AzB Silver Member
Silver Member
The next step I think is to have more precise dimensions. If anybody is kind enough to take some measurement on a existing bridge holder, it would be great. I'm actually in vacation but next week at work I can make a quick drawing to indicate the required measurement.

Thanks

Martin
 

Ssonerai

AzB Silver Member
Silver Member
Martin-
I have gathered from pictures in your earlier posts that you are a machinist.

This will probably make sense to you. I have made a system that mounts on the rail for my planer to cut gradual profiles on longish lengths, with a router and template follower. I have never used it for bending forms because it would not save time for the typical forms or work i get. But a system like this could generate a long M/F form for production. Such as an S-curve.....

As you know, remove the router & with a round nose stick tool in the clapper, it could do steel or Al. :grin-square:

This is sort of pool related - I have shown in the past that the planer is how i make shaft blanks, with a set of centers on the table & a tracer on the left column. :)

smt
 

Attachments

  • DSCN0066.jpg
    DSCN0066.jpg
    178.4 KB · Views: 147
Last edited:

xianmacx

AzB Silver Member
Silver Member
Thank you for the link

I want two of them, one on each side and also it's a nice challenging project for me, I really like to try new things.

Martin

I got that impression but wanted to share anyway. :)

Thanks for sharing the process, fun to watch.
 

bradsh98

Bradshaw Billiard Service
Silver Member
While this discussion may not be completely billiards related, it still applies to the manufacture of these bridge holders.


Aside from that, it is a really cool technology. Very interesting to see. Thanks for sharing!
 

trentfromtoledo

8onthebreaktoledo
Silver Member
Awesome post! IMO, this is PRODUCTIVE TALK!! Love it.

cant wait to see your finished product Martin, these Bridge holders will be awesome!

Trent from Toledo
 
Top