Glue Injection Techniques

When laminate or veneer is lifting, you can make a slit, inject adhesive, and clamp for a clean repair. Here are some detailed tips on getting the glue where it needs to go. February 20, 2008

Can anyone tell me how to inject glue (like under loose veneer)? The only way I can get it to work is to thin the glue way down, and try to keep it warm. Otherwise the needle clogs immediately and is useless. I have an assortment of medical syringes, and some I got from woodworking catalogs.

Forum Responses
(Cabinetmaking Forum)
From contributor G:
If you are doing repair of old wood veneer on wood substrate, then hot hide glue. If the old glue can be reached, try to scrape out as much as possible... if needed after the glue is under the surface, re-warm it with an iron.

From contributor D:
FastCap sells a CA glue called 2p-10 that we use for repairs on hardwood floors. It will easily pass through an 18 gauge veterinary needle. We drill a small hole and then inject the glue under the floor to fix squeaks or delaminated engineered floor layers. It is an awesome product and even makes strong end grain glue joints. It is a little pricey but I have not found its equal. It bonds well to old glue residue. Also available is an activator that makes it cure hard in less than 10 seconds when sprayed on a glue line. Be careful, the smallest amount of adhesive bonds skin to skin instantly. We have also used product from 18002GLUEIT and Woodworker Supply but think the 2p-10 is much stronger. Some of the other brands do not dry clear like 2p-10.

From contributor C:
I have some squeaky floors that need to be corrected. I can't find the 2p-10 on the web... Could you recommend a supplier?

From contributor D:
I buy my from the Ellettesville IN True Value Hardware Store. They make the 2p-10 in a medium, thick, and gel viscosity. The thicker the product, the better the gap filling. The thicker product will also go through a needle but you will do better with a 14 guage needle. The 8oz refills are way more economical than the 2oz bottles. Shelf life open is about 6 months. Longer if kept in the fridge. We have also masqued off seams in floors and dripped the glue in between two rows if the squeak is from edges rubbing.

From contributor T:
I've never been able to get syringes and glue to work. What I do is slit the veneer along the grain, lift an edge with a knife, then push in a couple dabs of PL Premium construction adhesive using a toothpick. Cover the slit with a piece of plastic (garbage bag), put a block on it and clamp for overnight. The cured glue does not stick to this type of plastic. Vapour barrier poly for houses works well too. The PL premium may ooze out of the slit, but this is desirable to seal the slit and is so thin as to be invisible. I don't even need to refinish.

From the original questioner:
Thanks for the hot hide glue recommendation. Problem is that the glue cools almost instantly in the narrow needle, and thickens. I think maybe a hotplate with a glass of hot water nearby will keep the glue and needle hot if I park them in the hot water. Thanks for the tip about re-warming with an iron.

Thanks for the info about 2p-10; I've been wondering about the activator - how far into a joint or under veneer will it work, or is it only good where it actually contacts the CA? Does the activator help when you inject it into the floor? What do you use to inject it?

Thanks for telling me about the slit method. I've done that many times, but never thought about using PL adhesive. I would usually slit with a razor, then push in Franklin glue with a thin pallet-knife. I can usually get the glue to squeeze over to the other side of the slit before clamping. I'll try to remember to get the Pl premium and try it. I don't remember ever seeing it anywhere.

From contributor D:
The activator only needs to contact a small portion of the glue to cause what seems like a chain reaction. We will just spray it on the surface so it runs into the hole and it works just fine.

From contributor C:
Let me clarify your method, if you don't mind.
1- Drill a hole in the floor
2- Spray activator into hole
3- Squeeze in glue via needle
4- Putty hole
Does this sound about right?

From contributor D:
Add "weight the area for an hour or so" and you got it.

From the original questioner:
I think you got the steps 1,2,3,4 wrong. I'm sure that the glue goes first, then the activator.

From contributor D:
The questioner is right... glue into hole, then activator into hole. Sorry I didn't pay good enough attention. Thanks for correction.

From contributor C:
Thanks for that clarification. I was wondering if the needle would get gummed up from contact with the activator.