Cracked cabinets

ani_101

So, with the extreme cold and dry furnace heat causing all sorts of wood problems, I now have cracked cabinets. On on of the cabinets, the particle board is showing a hairline crack, which goes all the way through to the cabinet inside as I had painted acoustiX on the inside, and that is showing the crack too. On the other one, it separated at the seams. I had used poplar hardwood dowels to align the multiple layers to build the cabinet - maybe these expanded and caused the panes to crack / separate. Here are the snaps of the cracks.

What is the best way to fix these? It took me a lot of time and effort to get these cut, glued and sanded. They were just about ready to be veneered and finished when I noticed the cracks. Between sanding and me noticing the cracks, they were sitting for about 3 weeks in my basement inside which is heated, but we did have the polar cold come through here in midwest and the furnace was overworking.

PaulEbert

This looks like a translam. Is that correct? Are there bracing layers near the cracks?

D1PP1N

I always use "sealcoat" shellac on the outside and inside of all my cabinets (usually use a foam roller and rag for hard to reach places. I would do that and then fill the cracks with epoxy. Its cheaper to buy a kit with 2 parts then the small ones and you get more. Its going to be messy but you can put down paper or plastic underneath the cabinets to stop the over running epoxy. If you go light with the epoxy it should stick fairly well. Its possible to epoxy the cabinet to your workbench so be aware of that and good luck getting it off!

Many might think sealing both sides is excessive but i think it helps stabilize the mdf /ply better. Also more important for sealed cabinets but a CNC uses a raw mdf sheet as a spoil board no holes and the machines vacuum pump can hold down a full 4x8 sheet of mdf or ply through a 4x8 sheet of mdf spoilboard so its definately porous. 

jhollander

It's hard to get an overall view of what might have caused this. I'd try to fix the cause first, then add a few pieces of wood on the outside to align the sides then split the cabinet open and glue it back together.

ani_101

It is a translam cabinet.

The second image, is a clean split at the seam, all around the cabinet, so maybe it can be split and re-glued, the first one, the particle board split. and it split half way and all way around the cabinet.

The cabinet still strong enough, held together by the poplar dowels which was used for aligning and gluing the layers. I just need to seal the crack. So maybe i'll try the epoxy thing and just coat the entire cabinet from the outside. There is no way of getting to the inside, as the end caps with the driver holes are also glued on.

Can epoxy be applied indoors or i need to wait for spring / summer?

ThumperTom

I would use a well ventilated area with the epoxy but I don't know if they have a low VOC kind you can use indoors.  Gorilla glue might be an option too.

Has anyone seen this happen with MDF?

Wolf

Yep- MDF will do this too.

D1PP1N

Do you have a bathroom with a vent in the basement? Thats how i used to get away with that stuff if its too cold out. Use painters tape on the side of the void your filling it will stop the epoxy from leaking through the cracks. Also you can use the quick set stuff and just shellac both sides after the epoxy dries too. Either way you have some sanding to do in your future!

ani_101

Thanks, yeah there is a bathroom downstairs, and I think it vents outside....!

jhollander

PVA glues have better hold strength than epoxy or polyurethane glues.  The advantage of the poly glue would be it's gap filling. The epoxy advantage is it's a reactive cure.

ani_101

jhollander said:

PVA glues have better hold strength than epoxy or polyurethane glues.  The advantage of the poly glue would be it's gap filling. The epoxy advantage is it's a reactive cure.

what is poly glue, and would it fill in / seal the crack? Again, not really required for strength, but to seal. if can be used indoor without too much nasty odor, even better.

This would then be sanded and finished (likely painted or veneered).

jhollander

Polyurethane glue is the Gorilla glue and the PL II construction adhesive, and probably some others. 
http://www.loctiteproducts.com/p/pl_ca_prem/overview/Loctite-PL-Premium-Polyurethane-Construction-Adhesive.htm

There's not much smell with the poly glues and they do provide some gap filling.  Adding some moisture around the joint before or after the glue up increases the expansion of the poly glue.

stephenk9

Ani

Can you insert a needle in the first pictured crack? They sell glue injectors for furniture repair at the woodwoking stores, probably also on Amazon. They have a bottle for the glue and a needle thats big enough to let the glue flow through it, but the needle is probably 1/16" or so. 

ani_101

I will try to insert a small diameter drill bit to check the side of the crack.

I always have a tough time sanding think squeeze out of gorilla glue.... end up sanding around the glue rather than the glue....

D1PP1N

I scrape glue off with a razor, chisel or card scraper. 

PaulEbert

Sealing the outside and not the inside may make the problem worse.

dcibel

That's a shitty deal with the crack - its always cold and dry where I live and I've not encountered anything like that, though I haven't built any translams either.

I wonder if the cause was the dowels, due to different rate of expansion and shrinkage. I just saw a video on FB recently of someone building a translam without the need for dowels to line everything up, I could dig it up for you if you're interested. This person used notched front and rear boards so each lamination had to slide into place, everything locked into place on the same front and rear panels.

D1PP1N

Im looking for a cheaper way to translam without as much waste. I think making a "C" shape might work okay but getting as many pieces out of a sheet is important const wise. High grade ply is expensive. 

dcibel

My idea for a translam with little waste was to basically just do translam with solid front and rear panels, so you just have the side panels that can utilize a lot more of the sheet of wood. Haven't convinced myself to spend the time building it though, my summers are still full of house renovations so I rarely get time to build fun stuff.

dcibel

Here's the video I was thinking of:

https://www.facebook.com/groups/1449567115312949/permalink/1995372194065769/

jhollander

I like the idea of making laminated flat panels of say 12 inches wide by 40 inches long so I can run them through the planer.  Then cut out the 4 side panels aprox 10 by 12 inch on 45s.  I could fold up the box and have the laminations still line up on the edges.

Ron_E

I too wondered about the dowels causing the crack. MDF is supposed to be pretty dimensionally stable and real wood isn't.

John, there was a recent trans-lam build in the PE forum that used strips of hardwood glued up as frames and stacked using dowels for alignment. http://techtalk.parts-express.com/forum/tech-talk-forum/1322990-mwaf-project-strafi-translam-build

Ron

  

jhollander

Ron, what I'm proposing is creating a translam board that is 1 inch thick by whatever then cutting out panels.

D1PP1N

Thats basically how i made these. 

jhollander

Nice, looks like a top to front wrap.  Those chamfers give me another idea.

D1PP1N

Yes the front, top, back were 1 piece mitered. I added 2 additional 3/4" sides on to it as well so sides were 1.5" think the top, bottom,front back were 1.25 thick. No braces lol needed.