Sealing of High Pressure Laminates (Welt rod)

[threeway]

Hello all,

My question concerns the sealing of two HPL wall panels, for use in a cleanroom. We're currently using silicone sealant (Dow Corning 798) but the way it looks depends strongly on the person applying the sealant.

The walls have a 4mm gap between them, and a depth of 6mm.
After the welding, the surface should be smooth, for contamination reasons. There's no need for a strong weld, since this is arranged by other means, as long as it holds it position for 20 years

We're now looking into the bonding/sealing by use of hot gas welding. The way they weld linoleum etc.

The question is, what materials could be used (with respect to mildew resistance as obliged by cleanroom regulatioins), and is it an easy weld process (on vertical gaps) ? Any hints or tips ?

Thanks in advance,

Threeway

 

[MikeHalloran]

I know little about hot gas welding of plastics, except that it's skill- intensive and slow, so your seams' appearance will still be dependent on who did them.

Could you add over-taping to your current process? I.e. firmly roll (wooden laminate roller) some adhesive tape over the caulked seam, and remove the tape after the caulking cures.




Mike Halloran
Pembroke Pines, FL, USA

 

[berkshire]

threeway (Mechanical)
You are saying these are high pressure laminates.
Are they Formica or melamine faced panels?
If so these materials do not lend themselves to welding in the true sense of the word.
PVC, HDPE, PET. could be welded, however the resultant weld surface would not meet clean-room standards unless the operator was extremely skilled or you were using automatic machinery. You do not want to cut or grind on the welded surface since this will leave a rough surface for bacteria to hide in.

Are you masking and post tooling, when you apply the caulk or are you trying to one shot this, straight from the gun? Doing clean room paneling I have had better results, tooling the caulk .
B.E.