wasted wood blanks with Silmar 41

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woodwzrd

woodwzrd

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I started this thread yesterday in what I thought was a new thread but actually ended up hijacking a different thread because I hit the wrong button when I intended to start a new thread. Any help would be greatly appreciated. Thanks

I have cast quite a few waste wood blanks using off the shelf fiberglass resin and have really never had any problems other than the color gets muted because of the tan color of the resin. I recently bought two gallons of Silmar 41 and I have cast some buckeye burl, cocobolo, elm burl, cherry burl, and some maple burl. With the buckeye and the cocobolo I had issues. I am using 7 drops of MEKL per ounce and I am casting in HDPE molds that I made. I am casting under 80# of pressure. With the cocobolo the blanks did not fully cure out in some spots mostly on the bottom. With the buckeye the resin seemed to want to pull away from wood. The rest seemed to cast ok. Is this a known problem with woods like buckeye and oily woods like cocobolo? I have quite a bit of coco and buckeye to cast so any help or advice would be greatly appreciated. Thank you in advance.
 
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sbell111 said:
BTW, 80 psi is way more pressure than you need for this and may lead to pot failure.
Click to expand...

Although others may jump in with "I always use 7.3k psi of whatever whatever and nothing ever happens"....40-60 is a good range, and SAFE range.
 
Alumilite is a better alternative for casting with wood. It actually penetrates the wood cell structure and binds to the wood. PR on the other hand not only shrinks away from the wood but just kinda of lays on the wood's surface. The fiber glass resin you were initially using also has a better affinity for wood than the PR which is the reason you didn't see any problems until you went to PR. I believe the FG resin is also PR but a different formulation. I am sure someone like MesquiteMan will jump in here and help with the details. You also may want to read the sticky thread that is at the top of the Casting forum, it gives a lot of the detail differences for PR and Alumilite.
 
I'm not at all convinced that alumilite can be counted on to actually penatrate the wood. It isn't nearly thin enough to reliably do so, in my opinion. That being said, it does work far better than PR in these blanks because it doesn't shrink.
 
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