Cedar sandblasting 101, test gone bad

[laserfred]

Hello guys,

we went to the local machine shop yesterday with a piece of cedar to test if they could help us with the sandblasting. I put a sandblast mask over a piece of red cedar plank and hand -cut some random shapes. They tried sandblasting it at 100psi with the beads they are using for their metal parts (rust removing and prepping), but the result was not quite acceptable.. Here are some photos I took of the piece (mask is still on). Anyone know what might be the problem ?

thanks in advance.

 

[nashvillesigns]

blasting

lets see.
blasting a soft organic wood that has more grain than a wheat field with a total controlled, but random material.
yea. that explains it.
you are better off with a router, sir.....

 

[Gino]

We always used silica sand in the beginning and switched to Aluminum oxide in later years.

However, your main problem can be seen in your second picture. You're not using vertical grain. What you're doing is like blasting a picnic table. There is nothing pretty about blasting away at flat grain.

 

[tbullo]

You need vertical grain boards and proper blast media like the other post says. Try some number 1 media, works for us.

 

[James Burke]

40 Grit Aluminum Oxide.JB

 

[laserfred]

I will check what kind of grit was used and also make sure of the right orientation for the wood grain.

thank you guys for the tips!

 

[Joe Crumley]

I'm way too late with this post but here's my input. I'd suggest having the blasting done by others. You CAN'T make money doing this every once in a while. One of the misnomers is the PSI. You don't want anything as high as 100. That will do nothing good except have a tendency to raise your mask. It's the CFM you are looking for. Our basting is done with 160 CFM at 80PSI. That gives plenty of air volume. That's what you are looking for not PSI. Perhaps I should write a little blurb on the topic but it's so rarely used today I doubt there is enough interest. Joe Crumley

 

[JR's]

I'm way too late with this post but here's my input. I'd suggest having the blasting done by others. You CAN'T make money doing this every once in a while. One of the misnomers is the PSI. You don't want anything as high as 100. That will do nothing good except have a tendency to raise your mask. It's the CFM you are looking for. Our basting is done with 160 CFM at 80PSI. That gives plenty of air volume. That's what you are looking for not PSI. Perhaps I should write a little blurb on the topic but it's so rarely used today I doubt there is enough interest. Joe Crumley

please do. thanks for the info.

JR

 

[Mosh]

+on the volume not pressure...also the wood should be a dryed cedar, NOT some cedar you picked up down at home depot for deck building....trust me it will be a huge difference....