nicked knives jointing laminates glued by Unibond 800

[Mike Leung]

I have been doing some bent laminations using Unibond 800. I cleaned up the edges with glue on it at the bandsaw and then jointed on my Inca with HSS tersa knives. After a few passes, I noticed that my new knives were nicked. How do you guys handle the Unibond glued up pieces on the jointer? Would M42 knives become nicked as well? Would I have to make the jump to carbide? I guess just switching the knives to joint glued up pieces would be a solution but I rather just use the same knives for all my tasks. Any Unibond users here with experience?

[Rob Woodman]

Urea formaldehyde glues are quite abrasive,( though excellent for curved laminations where spring back needs to be virtually nil) so while changing over to Tungsten carbide knives is an option, they will also suffer, albeit after more work.
By trimming the excess off on the bandsaw you saved the jointer knives a bit. Is it possible to clean up using a belt sander? Hand held or stationary type? (In your project) Belts are way cheaper than knives:D.

HTH Rob.

[Tim Lawson]

One of the reasons I switched to using epoxy. Epoxy is not as hard as UF; but I recommend not jointing or sawing until the epoxy has had 48 hrs to cure. If you're using 5 or more laminae the need for UF is diminished - spring is minimal with 5 or more laminae.

You can colour epoxy and change the thickness with microballoons. I also like the near infinite shelf life. I had to throw away too much UF. I use the West Systems epoxy and like it a lot. Their (free) guide to working with epoxy is really good too.

One other thought - you can use a scraper to remove the glue. I've used a card scraper and mounted scrapers effectively to clean up the bulk of the hardened glue. I'm really leery about sanding off hardened UF - do it outdoors if possible.

Good luck

Tim

[george wilson]

Can you slide the blades a little sideways,possibly on opposite directions? That will eliminate a nick unless the nick is too wide.

[Mike Leung]

I'm not that good on the belt sander to get a straight clean edge. Using epoxy in the future might be the solution. I like using the unibond For everthing else besides this issue and the toxicity when mixing and sanding. I slide my knives all the time. I am trying to find out If m42 and carbide will hold up. If this glue will Nick carbide knives, I will switch to epoxy for sure. I have used my flush trim bit to clean one edge and then bandsaw the opposite edge. I'll check the carbide on my bit to see if it has been nicked. I was so sure that carbide is tough enough for any glue.

[george wilson]

Carbide is actually very brittle. Like glass,it is very hard,but much less tough than HSS. I use it in my machine shop work. The situation has to be correct or carbide will break. The setup on a lathe or mill has to be rigid.

I don't know if carbide would help in your situation,and it will cost money to find out.