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Main Boards => The Bowyer's Bench => Topic started by: kenboonejr on July 26, 2021, 07:00:52 PM
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So... when I glued up my lams yesterday I coated the entire form with furniture wax, then laid plastic wrap over the bottom mold, put the glued up limb assembly in place put the pressure strip in place. I then wrapped several layers of filament tape around different parts of the limb and form to keep it in place. Then I put another layer of plastic wrap over that, then put the hose on, then bolted the top of the form in place.
Today, I go to take the limb out. I watched the Bingham's video again first, where it was like a 30 second process, cut the tape, peel the plastic wrap away, the metal pressure strip just pops up, they removed that, and out comes the limb.. yea ... no.. didn't happen like that for me. So got the tape all off, and started peeling the plastic wrap away which seemed to be glued up to it quite a bit, and once I had most of that gone.. the pressure strip was still in place. I had to grab the extended piece of the pressure strip and really use force to get it loose and was finally able to get that peeled off. It seems the limb is somewhat glued in place. Maybe I used the wrong kind of plastic wrap.. I dunno. I do have a lot of epoxy that squeezed out the size of the lams. Do I need to just get a chisel and chisel this excess epoxy away? Do I just try to get a blade under the limb and pry it up? Not sure how to proceed here and don't want to damage the limb.
Hoping ya'll can point me in the right direction.
I'll attach a picture of what it looks like now.
Thank you!
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Oh and by the way. The plastic wrap went half way down the mold too.. I just have already peeled away what was not stuck.
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Epoxy and pressure make for a tight interface, you might just need to yank that thing off.
How much epoxy did you use? Looks like a lot of squeeze-out.
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Do you have rubber hammer?
Or tap the epoxy buggers with a hammer while you are pulling on the recurve end sticking up
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You did all the right stuff, that epoxy down over the edges of form holds a lot. Mark has the solution, rubber hammer...
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Hey you guys are awesome! Rubber mallet got it loosened and then I was able to pull it off! That was great. Now need to get things cleaned up so I can glue up the second limb sometime this week.
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Good deal, I know they're tough to pull off. Make sure your formica strip is flush with your wood / sides of your form. I Always wax my form with furniture polish and let it dry on there plus a 3 to 4 mm plastic over the form. JF
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Holy crap upside down. Dang it
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Good deal, I know they're tough to pull off. Make sure your formica strip is flush with your wood / sides of your form. I Always wax my form with furniture polish and let it dry on there plus a 3 to 4 mm plastic over the form. JF
You know I just used regular old kitchen plastic wrap - is that part of my issue? Do I need to get a thicker mil plastic instead of the plastic wrap stuff? Also, you mentioned letting the furniture polish dry. So I pretty much waxed the form while the heat box was heating up. Should that have been done say the day before or hours before perhaps?
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Just use a good three to four mil plastic cut off about 10 inches off the roll and unfold it. Take that down to your form. I spray my form down with some old furniture polish, I don't know what it's called it's some old s***, pledge. Just in case. I let it dry I do that in between glueing up bows. JF
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I switched to wax paper and found it easier to handle and control.
All of mine get the rubber hammer. It's gotten to be SOP .
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Your good with the plastic wrap :thumbsup:
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I like the cheap plastic wrap that doesn't cling as much.
Also I take a scrap of lam or glass and wipe the excess glue down off the limb edge after airing (if you use the hose method) , this glue goes between the 2 layers of plastic and you can just rip it off after you pull it off form. It helps with that also by freeing up one side. I just grind the other side off with the thickness sander. If I didn't use that, I would wipe both sides down...
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My cling wrap usually gets torn at the washers but the rubber hammer works every time :thumbsup:
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I use the plastic wrap with the handle from Harbor Freight and double spiral wrap the entire bow . This pulls all the lams tight and avoids any glue from getting on the form and also it eliminates the need for washers to keep the lams from slipping making it possible to use the same form for different width or length limbs.
James
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I use the plastic wrap with the handle from Harbor Freight and double spiral wrap the entire bow . This pulls all the lams tight and avoids any glue from getting on the form and also it eliminates the need for washers to keep the lams from slipping making it possible to use the same form for different width or length limbs.
James
James if I am understanding you right. Once the limb of the recurve is glued up, you completely wrap the limb in the plastic, instead of laying the plastic on the form before and after the limb right? That does sound like a good method - especially to help keep things from slipping out of place.
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I'm curious, do you form guy's sand down smooth and put a sealer like shellac or something else on your forms before they are put to use? Wax is not going to do much on fresh plywood unless you get 20 coats on it!
Another thing, furniture wax has a melting point of around 140deg. Not a good choice for the hot box. Mold release wax or even some car waxes are far superior for this application.
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I'm curious, do you form guy's sand down smooth and put a sealer like shellac or something else on your forms before they are put to use? Wax is not going to do much on fresh plywood unless you get 20 coats on it!
Another thing, furniture wax has a melting point of around 140deg. Not a good choice for the hot box. Mold release wax or even some car waxes are far superior for this application.
Well I was just following the instructions that came with the Bingham's kit. And they said to use furniture wax so I put a coat on and went from there. Your temperature melting point is a good point though. What I am learning - is that there is a lot more to this than what the instructions show me ;) Now I will say that once I got the limb out, the mold cleaned up very quickly. The excess epoxy that was stuck on the edge of the mold just popped right off. The limb on the other hand has a lot of epoxy that oozed out that I need to clean up.
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I'm curious, do you form guy's sand down smooth and put a sealer like shellac or something else on your forms before they are put to use? Wax is not going to do much on fresh plywood unless you get 20 coats on it!
Another thing, furniture wax has a melting point of around 140deg. Not a good choice for the hot box. Mold release wax or even some car waxes are far superior for this application.
Flem the wax would need to be rubbed on every time for glue up.
I brush several coats of Shellac on the top of the form just to smooth it out.
I use a centering drill jig to drill a 1/4" hole dead center of the riser and form to pin every thing down, no lams slipping around.
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The limb on the other hand has a lot of epoxy that oozed out that I need to clean up.
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This is normal, you can do like KennyM said, I use my gloved finger sometimes.
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Rule # 2 always keep a dead blow hammer at reach. :biglaugh: :wavey:
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I use a centering drill jig to drill a 1/4" hole dead center of the riser and form to pin every thing down, no lams slipping around.
So in their plans, the form can account for 3 different size bows, 58" 60" and 62" and there is a hole you drill in the form and they give you a metal pin to put in the correct hole for the size bow you are building. They said to leave 3/8" of the pin sticking out and this is for the limb to rest against. The problem with that is when you stack all the laminations and wedge, that 3/8" only comes to a certain point in the wedge. Which means your bottom glass, tapered lam and the wedge can rest firmly against the pin, but the parallel and top glass can slide over the top of the pin.
It seems to me that pin should be the full height of all the laminations together to keep any slippage from occurring.
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I drill the hole slightly bigger than pin with enough depth to put a spring under it. Then the pressure strip can push it down and still catch the limb material.
It will take a little messing to get the hole right depth.
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I drill the hole slightly bigger than pin with enough depth to put a spring under it. Then the pressure strip can push it down and still catch the limb material.
It will take a little messing to get the hole right depth.
Okay that makes sense.
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I use a centering drill jig to drill a 1/4" hole dead center of the riser and form to pin every thing down, no lams slipping around.
So in their plans, the form can account for 3 different size bows, 58" 60" and 62" and there is a hole you drill in the form and they give you a metal pin to put in the correct hole for the size bow you are building. They said to leave 3/8" of the pin sticking out and this is for the limb to rest against. The problem with that is when you stack all the laminations and wedge, that 3/8" only comes to a certain point in the wedge. Which means your bottom glass, tapered lam and the wedge can rest firmly against the pin, but the parallel and top glass can slide over the top of the pin.
It seems to me that pin should be the full height of all the laminations together to keep any slippage from occurring.
I make my own wedges and lams so I would make all of it 1" longer and use the pin to keep it in place.
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Leave a 1/4 of the butt end without smooth-on and use super glue to glue it all together. You are going to cut the first 1/2 off anyway keeps stuff from slipping and sliding.
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Saw your video of the limb build and wanted to offer a few tips. Wiping the metal pressure strip with wax along with plastic wrap between the taped down bow, pressure strip and hose will help everything come off the form easier and keep things from getting a build up of tape residue and epoxy. Air it up slowly and ease it to max pressure rather than going straight to 60-70 psi and letting air out...this will prevent your lams from sliding around as much and prevent air bubbles. For more control and not having as much epoxy to sand off the edges try using a thin, flexible 1 1/2" putty knife to apply your epoxy. For better performance on your next bow use a core wood like maple, actionboo, etc... with the nicer but heavier woods like bocote as .030 veneers under the glass, that way your limb will be a little lighter and more responsive. Bowbuilding is an addictive hobby and I hope you enjoy the process.
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Saw your video of the limb build and wanted to offer a few tips. Wiping the metal pressure strip with wax along with plastic wrap between the taped down bow, pressure strip and hose will help everything come off the form easier and keep things from getting a build up of tape residue and epoxy. Air it up slowly and ease it to max pressure rather than going straight to 60-70 psi and letting air out...this will prevent your lams from sliding around as much and prevent air bubbles. For more control and not having as much epoxy to sand off the edges try using a thin, flexible 1 1/2" putty knife to apply your epoxy. For better performance on your next bow use a core wood like maple, actionboo, etc... with the nicer but heavier woods like bocote as .030 veneers under the glass, that way your limb will be a little lighter and more responsive. Bowbuilding is an addictive hobby and I hope you enjoy the process.
Thanks so much for that feedback. I actually did wax the pressure strip but I think I put the plastic wrap over the pressure strip instead of under it like you said. As far as putting air in I actually started with a bicycle pump, but for some reason in the mold I couldn't get it above 30 PSI. When I tested it for water leaks I pumped it all the way up to 60+ PSI with that pump, but in the mold, it wouldn't get above 30. So that is when I took the compressor to it. That makes sense though about it sliding around if it is pumped up too fast. You also confirmed my thinking about the foam brush I was using to apply it with. I felt like I was using too much epoxy and that brush didn't seem to hold up real well. My wife actually picked up several of those thin plastic putty knives you mentioned at Lowe's yesterday and I am going to try gluing up the second limb in just a little bit using those plastic putty knives instead of the foam brush. So thanks for giving me confirmation on that.
As far as what you mentioned about using something different for the core wood.. could you explain that a little more. Again this is my first build, and I am finding out quickly if it wasn't for this forum the video and book from Bingham's although good - leaves a lot of things out and the video just makes it like everything fits so easy and it goes so quick. So the kit I have, each limb has the 5 parts. The inner and outer glass, then a tapered and parallel bocote lam, then the wedge. So in your description for a lighter faster limb, what would the layup look like?
Thanks again for the feedback. I am learning a ton form doing this as well as from the fine folks on this forum!
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before you drill your holes in the riser and limbs tells how you plan on doing it.
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I think we've all had those mistakes learning how to glue up a bow. Things get slippery. And you're nervous as hell, want to make sure it turns out right. Strive for the best. JF
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I think we've all had those mistakes learning how to glue up a bow. Things get slippery. And you're nervous as hell, want to make sure it turns out right. Strive for the best. JF
No kidding on being nervous man. I just glued up my second limb and put it in the hot box about 20 mins ago and I was only "slightly" less nervous.
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It will get better, remember you're supposed to be having fun 🏹 JF
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You would be adding 1 more layer of wood to your limb. Clear glass on the outside followed by thin parallel veneers of heavy, exotic wood and make the inner lamination a taper of actionboo (laminated bamboo).
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You would be adding 1 more layer of wood to your limb. Clear glass on the outside followed by thin parallel veneers of heavy, exotic wood and make the inner lamination a taper of actionboo (laminated bamboo).
Yea ok that is what I was thinking when you said that. So the thickness and size would be adjusted in the design then for hoped for draw weight at draw length then.