media blasting an engine

[zx10crazy]

Got a question for some of you guys hope I can get some good feed back so I can figure my next move on this project I have a freshly rebuilt Honda line 300 motor that the paint is really rough looking but the motor has been completely gone through can I media blast the motor the way it sits if I protect exhaust port intake boot and seals? Or do you guys think this maybe a disaster waiting to happen? I am doing a complete restore on the rest of the machine and want the motor to match any good input would be awesome thanks in advance

[slashfan7964]

How far are you really willing to go on your build?

[yaegerb]

I have done a few motors, maybe flyingw or others will chime in that have done the same, but in my opinion, its a disaster waiting to happen. You should be using fine to medium (depending on mfg) glass bead to blast and even with coverage of your intake and exhaust, dust will find its way in. Also, you will likely destroy the gaskets on the case/head which could also allow fine particulates to enter the motor. Bottom line, when sandblasting you should do that when the motor is in pieces and before a rebuild.

A secondary option (painstaking) would be to scotch brite the entire motor by hand to scuff up the old paint and then spray some PJ1 fast black or high temp VHT high temp red paint....whatever case color you want.

just my .02

[barnett468]

hello;

yes you "can" media blast it. if you do, i suggest using high quality yellow masking tape otherwise it will not stick and is thin so it will require more layers.

jam some paper towels in the port for added insurance and use around 4 layers of tape and don't blast the tape.

obviously tape off all other things like the breather and the clutch arm and seal and the shift shaft and seal etc.. do those areas by hand if needed.


you also need to decide on the media to be used. some sand/silica/glass etc.. is sharp and will leave a slightly coarse surface. i would use plastic or similar.

you can also use aircraft stripper. it will take longer and is EXTREMELY messy so you need to do it in your neighbors yard. if you go that route be sure to wear goggles and plastic gloves and do it in the open where there is a lot of fresh air and do NOT ever, ever, breath the fumes ever, never.



Here's my avatar. I named her Bacon. Isn’t she cute?

Hi, my name is Bacon Aren't I cute.

http://t0.gstatic.com/images?q=tbn:ANd9GcTDheK_NT7A9cIdJnV_1Pg7lGbLDWNu5 AVQnY60FToKElt_Wip72n1nHA

[El Camexican]

Don’t use sand on aluminum and don’t even think about bead blasting it as a whole. It WILL get into something.

I’ve never done it, but I hear that walnut shells and dry ice can both be used for something like this.

[barnett468]

PS - Sorry I forgot, I would also use low pressure like around 20 - 25 and hope that it will be enough and don't stick the nozzle closer than around 10" at the critical/danger areas.

Your engine will have a fine dust left on it from the media. I would blow it off then rinse it off with water and dawn or lemon joy and use a tooth brush on the side cover gaskets and cylinder fins.

As Yaegerb implied, it has its potential dangers, however, I have done similar several times out of necessity and never had a prob. just be sure that the surface the tape goes on is hermetically clean, lol.

[barnett468]

I have used walnut shell several times but only in huge blaster on car bodies. The shell is great for bodies because it does not damage the surface and does not warp the metal. Warped metal would not be good on a $150,000.00 car, lol. They also use it on some of the Disneyland rides when they are redoing them [a bit of Disney trivia].

They also sell it for small blasting cabinets but I have never used it in one. I'm sure it would work xlnt on your engine, however, it leaves an ultra fine dust and the owner of the sand blaster might be less than enamored by the inside of his blaster when you are done if you used it, lol.

Walnut shell

http://www.eastwood.com/blast-media-walnut-shells-50-lb.html?srccode=ga220010&gclid=CK-MpcmR6b0CFa_m7AodyQwAyg

[badandy]

I have blasted many parts... I sooooo wouldn't recommend an assembled engine! It's not that you can't.... it's just really risky, and you won't know until it's too late...

[rg97]

+1 on a disaster waiting to happen. You can protect all you want, but I work with glass beads just about every day and they goes EVERYWHERE.
Like, slashfan said, its going to depend on if you want a nice looking motor with paint that will last, but is painstaking and time consuming (dissassembly, blasting, paint, reassembly), or you can try and do it the quick and seemingly easy way and possibly pay the price.
Your call on it. You've heard pros and cons from both sides.

[DohcBikes]

Walnut shell works great. Fully assembled engines get blasted every day.

Plug the holes, clean the engine before you unplug the holes.