Troubles with the New Unibond 800 Formula
11/21/12
My shop has been happily using unibond 800 on our vaneer projects for many years now, but recently the formula has been changed, and we are getting unsatisfactory results from the new formula. We are able to peel the vaneers right off of the substrate after it has been in the press for many hours. The photo shows that we have good glue coverage, and how easily the vaneer was pulled off. Is anyone else having the same problem with the new formula?
Or does anyone have any suggestions for a new product for us to try?
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11/21/12 #2: Troubles with the New Unibond 800 F ...
Website: http://www.veneersystems.com
Are you pressing this at 70 F or warmer? Also are you sure the mixture is correct?
Is your core at room temperature or is it cold?
You may also want to check your bag for leaks.
11/21/12 #3: Troubles with the New Unibond 800 F ...
I can tell you that it was 79 degrees when we did the pressing in that photo. The ratio of the mix was set for a slow set up time. We are measuring the resin and hardener by weight, and we used 7 oz of hardener to 105 oz of resin, which complies to the 1 to 15 mixing ratio for a slow set.
Our vacuum tables are working just fine. We actually just replaced the gaskets in our table and we are getting better seal than we were before unibond changed their formula. Not exceptionally better, but better.
The reason we have been using a slow set up time is because we were having problems with the fast set up time and shelf life. We were finding that as the resin got older it was setting up before we could finish spreading it. At that point we stopped leaving the resin out in the shop environment and started storing it in the fridge. At first we were not letting the resin return back to room temperature before we were using it. We had problems with adhesion then, but then we started bringing the resin out the day before we were going to press and we are still having the same problem.
11/30/12 #4: Troubles with the New Unibond 800 F ...
Switch to Pro Glue dry resin UF, comes in powder that mixes easily with water, has a low formaldehyde content, very long shelf life since its powder, and it's less expensive, at least from the west coast. Haven't had any problems after several years of use.
Bob
1/23/13 #5: Troubles with the New Unibond 800 F ...
Website: http://www.earlkelly.com
I will second Bob's recommendation of Pro Glue. I really like their White/transparent version. The glue is white but in glue line thickness it's practically transparent. Perfect for maple and other light woods.
1/23/13 #6: Troubles with the New Unibond 800 F ...
Website: http://www.veneersystems.com
We also sell a powder plastic resin that dries dark brown but can be tinted with titanium dioxide to lighten the glue.
Also another tip for new Unibond 800 full cure is 48 hours. It doesn't have to be in the bag that long that is just the point at which you will have the strongest bond.
Product Link
10/26/14 #7: Troubles with the New Unibond 800 F ...
Website: pricecabinets.com
Several problems with the new lower formaldehyde (4% to .04%) Unibond 800. Partial sheet lifts as well as entire sheets,
no matter what the backer or substrate.
Double mixing, variations in the ratio, glue
in refrig. as we are in Fl., heating pads,and
the local medicine man chanting as we
roll out the glue.
I am done with what was the best veneer
glue I have used after 35 years. I paid the
price with water base and checking-once
cost me $ 42,000.00 to reveneer an entire
media room. Went back to the Unibond
and I am looking for better. Resorcinol
may be the answer, but 14 hours to set is a long wait, even with 3 or 4 vacuum bags
full time.
11/27/15 #8: Troubles with the New Unibond 800 F ...
I'm reviving this old Unibond 800 thread to see if there is any improvement in the situation.
Are you folks who had trouble still using Unibond 800 but with improved results or have you permanently switched to something else.
Thanks for the input.
BH Davis
10/16/20 #12: Troubles with the New Unibond 800 F ...
Website: http://RedHookDesignAlliance.com
Hi,
Found this thread while looking for a repair solution for de-laminating Unibond 800. I'm new to laminating but after 45 years of woodworking I have a solid background with glues and glue-ups. I'm fabricating a rift sawn oak veneer entrance for a 125 year old commercial building. Not having done veneers, and as usual, I jumped in both feet, spent hours and hours boning up on veneers, bought a new, very serious vacuum bag system, and, using Uni-Bond 800, went at it. I'm very precise in all aspects of my work (digital readouts on saws, planers, etc) so I am using a gram scale for mix ratios. I'm applying 1/18th" thick veneer on cabinet grade plywood roughed with 80 grit on a Festool Rotex sander. I'm getting a lot of de-lamination on glue ups that are days out of the press. They look fantastic coming out of the press. I'm suspecting the Unibond and seeing the photos others have posted, it seems plausible. First question is someone else's opinion as to why, and the second question is can these panels be saved with a hot iron or some other method? Thanks for any light that can be shed on the problem.
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