Hello all:
I,m new here and I hope you can help me with a couple of items.
I am glueing up an exterior fir beam, finished size will be 4″x8″ by 14′ long with a 14′ radius. The material is kiln dried 1/2″ by 4 1/2″ edge grain strip. I would like to know the most suitable glue, it should leave a descrete glue line, be weather proof, have a long working time (45 min.plus ?), some gap filling properties, minimal spring back and it would be nice if it didn’t break the bank, although I am certainly willing to pay for the right product.
The other item is, I am wundering how much spring back to allow for with the prescribed glue and how to be sure I do not squeaze out too much glue.
The strips are plained smooth, I am planning on anchoring a right angle clamping bracket to a concrete slab every 12″ through the 14′ arch and using Jorgenson heavy duty fast acting bar clamps with about a 6″ throat depth to clamp all 16 strips at once (hence the relatively long open time). I plan to start in the middle and with assistance work my way to each end. I am also planning on squeazing the assembly down to the floor with poly covered cawls so as to keep the works from twisting.
To re-cap:
- what kind of glue
- how much spring back
- is one clamp every 12″ enough
- how long to leave clamped
- how to ensure enough glue
- Thanks in advance
Replies
I'd seriously consider doing it with epoxy. Have a look at West System products. I have only limited experience with this kind of thing, but I've been impressed with the options and the results.
As far as clamping is concerned - do a mock up without adhesive, and you'll know the answers to all the clamping questions, including how long a working time you really need.
DR
I build custom furniture not 14' beams but... The West System Epoxy is one that I would check into along with Weld Wood. They make several types of adhesives but I would look into their powdered one. Weld Wood works very well and has somewhat of a dark glue line that might blend into your beam? As for clamps... My Motto is, if a little is good... a lot HAS to be Great! Seriously though, I would do a mock up/ dry fit and see how that works out. It will tell you if you have enough help as well. How do you plan on making the radius? I take it you already have some kind of form or a peg system to lay up into? If that's the case, it might limit you on how many clamps you can use since the vertical pegs might limit you. As for clamping times etc. It all depends on the adhesive as well as the temp and humidity where you will be making Noahs Arc. ; )
Another thing you might try is finding a mill close by that makes them on a regular basis and see what they have to say & use etc. I hoped this helped a little and Good Luck.
It's all good advice and I am thankfull for it, I am going to try and dig up some info from a West System rep. will let you know how I make out.
I have made many outdoor and indoor beams and other laminations for many years and have never had one fail yet. I used to use what they called marine resin glue. Now the same product is called plastic resin glue. It is a tan or light brown colored powder that you mix with water. The nice thing about that glue is that you can vary the amount of water to the kind of weather conditions and the amount of surface you must cover. More water gives you a thinner glue and a little more time to work with it. You need to have a glue for laminating that will not creep. If the glue creeps the lamination will move or possibly separate and come apart.
When they changed the name of that glue I took a small amount of glue that hardened and kept it in water for about one week and not any part of it broke down or changed the color of the water I had it in. I was told that they could not call it waterproof like epoxy or resorcinol becausee it did not meet the same criteria. Steam or very hot water will cause it to break down some.
The glue I am talking about is found at http://www.acehardware.com/sm-dap-and-reg-weldwood-and-reg-plastic-resin-glue-00204--pi-1409486.html
I have been able to get it through any place which is an Ace Hardware.
Thanks for the advice gb93433 (any relation to R2D2?). Would you happen to know if there is a problem with too much clamping pressure causing a starved glue joint from squeaze out? aka epoxy. Also what about open working time for this sort of glue and minimum room tempature. I am going to do a dry run on Monday to see how much working time I need and how much clamping force I will require as well as how many extra hands. I hope to be able to glue up all nineteen laminations at once but this dry run should tell me what is possable. Thanks in advance.....Gary/wazoo
I have never experienced any problem with to much pressure in laminating anything. The surface area is so great. On the outside of the stock I use some thin pieces the length of the piece to be glued to use in clamping so that I do not have to worry about making marks on the lamination. Between the mold and stock I use wax paper or something which will keep the stock from sticking to the mold.I thin the glue to about the consistency of honey. I put clamps on both sides of the lamination about every six inches or less. Outside curves will not take near as many clamps as inside curves. I start from the center and completely tighten each clamp along the way so that there will not be any bumps or areas which were not tightened. Regarding the glue: the container will tell you what the open time will be at a given temperature. Thinning the glue will give you a little more open time. Usually I try to get the laminations together in less than 30 minutes. Three years ago I glued up a lamination with an inside and outside curve with a tighter radius and 32 laminations. It took me about 30 minutes to get done. It was quite a workout though.I would suggest that you leave the clamps on for at least two days. More is better. That is a lot of surface area inside with not much room for the water to evaporate. To spread the glue I mix up what I think will be enough plus some more and spread it with a paint roller.
Edited 4/1/2006 4:37 pm by gb93433
Paint roller? like it! didn't think of that...........thanks again
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