BetterBond Heat Lock™ Frequently Asked Questions

How do I apply Heat Lock?
Please click here to learn how Heat Lock adhesive is applied.

What tools do I need to use Heat Lock?
In addition to veneer, substrate material and the HL adhesive, you'll need a clothes iron, glue roller, and a small piece of cotton or flannel cloth. You may also find it helpful to have masking tape available.

Do I need to do a practice sheet first?
Yes! It’s always a good idea to do a test panel with some scrap before you begin.

What species does this glue work with?
We've tested Heat Lock with 60 different species of wood and achieved excellent results with each one. Even oily woods like teak respond well to Heat Lock. The only veneers with some issues are quilted bubinga and occasionally with figured mahogany. The extremely dense wood cells in this species do not respond well to heat.

How much heat is needed to bond a veneer with Heat Lock?
Bonding is best done with the clothes iron on set to medium/high. On some irons, this will be the "cotton" setting which is approximately 193°F.

Can I use Heat Lock for seaming two or more veneers together?
Bookmatching or any other veneer seaming technique can be very difficult with Heat Lock due to veneer shrinkage from the heat of the iron. However, there is a possible "work-around" for the problem.
To solve the shrinking problem, you can place a straight piece of clothes hanger wire about 2" away from the seam. Then iron down the seam. Next, pull the clothes hanger wire out and iron down the bubble that it left behind. This will force the seam tight. This technique requires a bit of practice but it does work well once you get an idea of how much shrinking will occur from the iron.

What kind of wood grains are compatible with Heat Lock?
Burl veneer is probably the best grain with Heat Lock. The interlocking and variant grain pattern in a burl allows the wood cells to respond to heat without splitting or cracking. Quilted, curly, bird's eye, and straight grain veneer should be treated with veneer softener to minimize splitting near the edges.

Why do I need veneer softener when ironing the veneer?
Veneer softener makes wood cells pliable and allows them contract and expand without separating and thereby causing a split.

Will this adhesive work with paperbacked and 2 ply veneers?
Heat Lock will work very well with paper-backed adhesives. Two-ply veneers have a tendency to require much more labor because the extra layer of wood on the back of the veneer insulates the glue from the heat of the iron.

Can I cut small strips of veneer to make custom edgebanding?
Yes! Heat Lock is great for edgebanding. Be sure to apply you banding before you veneer the top of the panel.

Do I need to veneer both sides of the panel?
Yes. Most panels less than 3/4" thick will warp if both sides are not veneered. This is a phenomenon that affects all forms of veneering including vacuum press work.

Why do I need the cotton or flannel cloth?
The cloth is placed between the iron and the veneer to prevent scorching. This also reduces direct heat on the veneer which will minimize splitting caused by excessive heat or poorly manufactured veneer.

Can I use Heat Lock to repair piece of damage or lifted veneer?
Veneer has a tendency to shrink from the heat of the clothes iron which will leave a gap between the edge of the damaged/delaminated veneer and the edge of the original veneer. In this case, the best option is to use BetterBond cold press veneer glue and place some weight on top of the delaminated veneer while it dries.

My project is fairly large. How much coverage can I expect from a pint?
Heat Lock was designed for woodworkers and cabinetmakers who do not want to invest in a vacuum press for small veneer projects. A pint size bottle of Heat Lock will cover approximately 45 square feet of veneer.

Do you have any local distributors for Heat Lock?
At this time, and Highland Hardware are the only distributors of Heat Lock iron-on veneer adhesive. We are looking for additional distributors. Please contact us for further information.

Does the color of the adhesive show through on lighter wood species like maple?
Due to the thick consistency of Heat Lock, bleed-through is very unlikely so even lighter woods like sycamore and maple are not affected by the color of the adhesive.

What kind of substrate can I use for my panel?
Heat Lock will work with a variety of substrate materials such as wood, plywood, MDF and particle board. Make sure the substrate is clean and porous. Some substrates can be made more porous by scuff sanding with 100 grit sandpaper. You can test the porosity of the substrate by placing a few drops of water on the substrate. If the water is not absorbed by the substrate within 10 seconds, you may find that the Heat Lock glue will not work.

When I applied the adhesive, my veneer started to curl up. What should I do?
Before applying Heat Lock, its best to tape down the edges of the veneer to a piece of cardboard. Leave the veneer taped down until the glue is set and the panel is ready to be heated.

What kind of finish can I use with Heat Lock and how soon can I use the panel after it has been veneered?
It's best to let the adhesive fully harden before staining/finishing the veneered surface. This normally takes a few hours. Since Heat Lock cures hard, practically any non-water based stain or finish can be applied.

Can I use yellow glue for iron-on veneer as well?
There are many websites that say you can use yellow glue for iron-on veneering. I find it so disheartening that anyone would deceive their audience but it seems to be common on the internet these days. They make a 60 second video, post it on YouTube, and now they are an expert who swindles thousands of people. What a shame. While you can use a clothes iron to re-activate yellow glue, the one thing you don't see in those misleading "tutorials" is what happens one season later when the ambient humidity changes and the wood cells in the veneer shrink or expand. When this happens, the yellow glue lets the veneer move. This is called "cold creep". It allows the veneer edges to lift and the center parts of the veneer either crack or bubble depending on the direction of the humidity change. Heat Lock glue dries much harder so the cold creep simply does not happen.

Can I use a waterbased stain and/or topcoat with Heat Lock?
If the bond is strong between the substrate and veneer. A waterbased finish should be no problem. Once the Heat Lock glue is dry, water will not affect the bond strength. However, if the bond is not adequate (caused by lack of glue or heat), a waterbased finish can cause bubbling since wood cells expand with water. If you must use a waterbased finish, allow the panel to cool down from the ironing process and then spritz the entire project with water. If the bond is poor, the water will cause any loose or poorly adhered areas to bubble up. You can reheat the panel (within 24 hours of application) and get the glue to re-stick and the bubbles to disappear.

My veneered panel has some bubbled areas on it. What should I do?
Bubbles are caused by poor adhesion between the veneer and the substrate. This often occurs when an inadequate amount of adhesive is used on the veneer and substrate. To avoid this, it is highly recommended that an inexpensive, dedicated glue roller is used to apply the adhesive. Bubbles can also be caused by lack of heat from the iron. It is important to work slowly and methodically when applying the heat to the veneered panel.

To fix a problem area, cut a fine slit into the bubble and inject a bit of Heat Lock inside. Allow it to set up for several minutes and then iron down the imperfection.

If your panel already has a finish applied, you wont be able to use heat to re-activate the bond. After 24 hours, the cross linkers in Heat Lock have set up and are much less re-activatable with heat. In this case, use this process to flatten the bubbles:

  1. Apply a coat of paste wax to the finished surface.
  2. Slit the bubbles and inject a small amount of Heat Lock inside.
  3. Massage the bubble to work the glue around inside. Wipe off any excess that comes back out of the bubble.
  4. Place a piece of wax paper over the bubble and then place a piece of 3/4" plywood (8" x 8") on top of the wax paper.
  5. Put at least 20 lbs of weight on the plywood and let the glue cure for 6 hours.
  6. Remove the weight, plywood, and wax paper.
  7. Gently scrape off any excess glue that may have squeezed out of the slit from step 2 above. The paste wax should make this step very easy.

After my project is veneered with Heat Lock, can I reactivate the glue area to remove a veneer?
The cross polymers in Heat Lock (which are what makes it so durable) start to set up within a few hours after the veneered panel has dried. Once this happens, the glue is not nearly as re-activatable with heat. While I suspect a clothes iron can create enough heat to allow removal, I doubt most pieces of veneer could withstand that much intense heat and would not come off cleanly.

Can I use the Heat Lock glue in a heated dry press?
Yes. If you have access to this type of press, Heat Lock can be used. We have been told by Heat Lock users that 150-180° for seven minutes works very well.