hot melt glues

[don carmen]

I bought a PAM Technologies hot melt glue gun last year(HB220). I finally used it on an actual job the other day. I ripped out some corner blocks on door and window casings

(by others) and replaced them with my own. I used Titebond construction as the adhesive

due to cavities in the drywall etc. but used the hot melt to hold things in place during cure time. Worked great!!

Now I am reading about different hot melt systems with polyurethane adhesives etc. It is such a time saver that I think it would be a good idea for discussion.

I will be happy to contribute as it is a road I will be going down.

Don.

[Ken Darga]

Polyurethane Hot Melt

Use up a whole tube in one day. It's hard to restart a partially used tube that has cooled and has been resealed. 

[Ken Darga]

HMA (hot-melt adhesives) are very useful for many tasks---

for small to large jobs---

for permanent bonding as well as temporary bonding.

 

In addition to bonding surfaces together, hot-melt glue can be used to fill gaps. 

 

The glue is tacky when hot, and solidifies in a few seconds to one minute.

 

Hot melt adhesives provide several advantages over solvent-based adhesives.

 

Glue guns come in low-temperature and high-temperature (hot-melt) versions.

 Low-temperature glue guns operate at approximately 250 °F (121 °C) and are well suited when high temperatures are undesirable, such as gluing lace and cloth. 

High-temperature guns operate at approximately 380 °F (193 °C) and produce a stronger bond.

Dual-heat guns feature a switch for both low- and high-temperature use.

 

The glue-gun with the "trigger control" feature is beneficial---the flow stops when the trigger is released.

 

A tool rest prevents accidental contact with or damaging surfaces.

TIP: Place the glue gun in a metal pan, such as a baking sheet  with an upturned flange to rest the glue gun, during heating and cooling.

 

Bonds must be made quickly before the glue has time to harden. Usually it must be applied accurately with the glue gun, as it cannot easily be spread, but it is always possible at any time to melt and spread the glue with a heat gun which helps when bonding larger areas.

CAUTION:  DO NOT touch the gun time---it gets very hot.

DO NOT touch the melted glue---it will stick to your skin and serious burns will occur.

 

Small diameters glue sticks are great for hobby and craft uses, and when only small amounts of glue is needed.   The smaller diameter allow for more rapid heating.

(The small glue sticks are generally available at hobby/craft stores).

 

Long sticks more useful when performing larger glue-ups.

 

Glue stick are also available, is a "caulking" formula---useful for fill voids.

 

Very helpful to have a separate gun for various glue-set times.

(Avoids reheating the glue to remove and change glue sticks.  

Remaining residue from previous glue-stick needs to be cleaned out, when changing glue-sticks).

 

 

A "small dab will do ya" when only a temporary bond is needed.

 

CONS:

Some of the disadvantages involve thermal load of the substrate, limiting use to substrates not sensitive to higher temperatures, and loss of bond strength at higher temperatures, up to complete melting of the adhesive.

HMAs do not lose thickness during solidifying; solvent-based adhesives may lose up to 50-70% of layer thickness during drying.

[Ken Darga]

PS---HMA's

DO NOT use for bonding/joining structual members.