Reply
 
Thread Tools Display Modes
 
Old 05-15-2019, 07:50 PM   #1
Mini-Skoolie
 
Join Date: Feb 2019
Location: Central Connecticut
Posts: 13
Year: 1992
Coachwork: international
Chassis: Front engine
Engine: mechanical DT466
Rated Cap: 71+
Sandblasting material

Hi guys,
I am going to be sandblasting the undercarriage on my bus and wondered what grit/ material everyone used? I was planning on getting a portable sandblaster from harbor freight and going to town.
Thanks
Thetireddad is offline   Reply With Quote
Old 05-15-2019, 07:59 PM   #2
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 5,748
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
I do a lot of sandblasting for my business. For all the small stuff I use a fine grit coal slag (Black Diamond). For lager things my friend does them in his booth at his blast business and uses a 000 sand.
Here's some info that will help you decide which grit to use.

https://www.blackdiamondabrasives.co...ond-coal-slag/
o1marc is offline   Reply With Quote
Old 05-16-2019, 08:35 AM   #3
Mini-Skoolie
 
Join Date: May 2015
Location: Miami, Fl.
Posts: 67
Year: 1999
Chassis: Amtran / International
Engine: DT466E-Md3060
Quote:
Originally Posted by Thetireddad View Post
Hi guys,
I am going to be sandblasting the undercarriage on my bus and wondered what grit/ material everyone used? I was planning on getting a portable sandblaster from harbor freight and going to town.
Thanks

Greetings Tired Dad,

I do lots of sandblasting here in South Florida so I can speak from first hand experience.

First I would like to agree with o1Marc, Coal slag aka black beauty is great stuff but there their are other options that I would like to share with you.

I personally do not use COAL SLAG outside of a blast cabinet because of the dust cloud it leaves but it is great stuff when used in a blast cabinet or with a wet blasting system such as mine. I have a Farrow system in my shop to blast wet.

Any dry blasting used will leave some sort of dust cloud of some sort. This is important not just because of the cleanup issues but the last thing you want to do is breathe in any of the blasting dust materials while you are doing this type of work.


WARNING: NEVER OPEN AIR DRY BLAST WITH SAND !!!


Dry blasting with sand creates microscopic fine dust containing free silica which WILL cause Silicosis in the lungs... this is only curable by replacing the lungs so please do not do dry blast with Sand!!

Wet blasting with sand is acceptable but only if you have the right equipment!

Ok...
If you are going to be under the bus and blasting very small problem spots a dry Harbor freight pot will work just fine but you WILL need to use some sort of personal protection equipment not only for your lungs but also for your eyes and ears...yes ears! Any and all blast material will find its way into the ear canals.

In order to avoid this I personally use a Nova 3 air feed blast helmet along with a disposable tyvec paper suit.

For the one time backyard user I would suggest you look at using a pressure washer with a sandblasting tip attached to it...works wonders !!

Here is a northern tool video on the pressure washer sandblast attachment.



You will get soaking wet while doing this but there are advantages that make it all worthwhile.

You wont be breathing in any dust because it is all wet and will immediately fall to the ground!

You can use screened blasting sand, not play sand. Play sand from the big box stores is full of larger particles that will clog up the tip!
If using sand (wet), I would recommend a 20/30 grit for the underside of the bus.

But, I would personally recommend using crushed glass instead. It contains practically no free silica, it is very reasonably priced and the crushed glass by itself is safe to dispose of in the trash. Rust under the bus is typically not a hazardous waste so you would be safe in dumping that in the trash to.
If you use crushed glass use either a fine or medium grit.

After you finish blasting you will want to treat the clean raw steel with some sort of rust treatment. My number one choice is OSPHO.

Raw clean steel that has been recently blasted wet or dry will begin to flash rust almost immediately. You do not want to blast then paint without treating as rust WILL begin to form under the paint and you will have a paint failure event sooner or later. OSPHO is cheap so remember an ounce of prevention is worth a pound of cure.

Once you clean, treat and are ready for paint please be sure to use an epoxy primer to seal in the blasted work area. Regular 2k primer will bleed, will allow moisture to penetrate thus creating the opportunity for more rust growth.

I hope you find this info helpful and again please, PLEASE, DO NOT DRY BLAST WITH SAND !!!

Oh yeah I almost forgot, no matter what blasting media you use, be prepared to use quite a bit. On a 30 foot boat, while taking off the antifoul bottom paint I will typically use about 600-700 lbs of sand. ( remember I blast wet not dry!)
ewo1 is offline   Reply With Quote
Old 05-16-2019, 09:42 AM   #4
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 1,008
Chassis: still looking for my bus
Quote:
Originally Posted by ewo1 View Post
Greetings Tired Dad,

I do lots of sandblasting here in South Florida so I can speak from first hand experience.

First I would like to agree with o1Marc, Coal slag aka black beauty is great stuff but there their are other options that I would like to share with you.

I personally do not use COAL SLAG outside of a blast cabinet because of the dust cloud it leaves but it is great stuff when used in a blast cabinet or with a wet blasting system such as mine. I have a Farrow system in my shop to blast wet.

Any dry blasting used will leave some sort of dust cloud of some sort. This is important not just because of the cleanup issues but the last thing you want to do is breathe in any of the blasting dust materials while you are doing this type of work.


WARNING: NEVER OPEN AIR DRY BLAST WITH SAND !!!


Dry blasting with sand creates microscopic fine dust containing free silica which WILL cause Silicosis in the lungs... this is only curable by replacing the lungs so please do not do dry blast with Sand!!

Wet blasting with sand is acceptable but only if you have the right equipment!

Ok...
If you are going to be under the bus and blasting very small problem spots a dry Harbor freight pot will work just fine but you WILL need to use some sort of personal protection equipment not only for your lungs but also for your eyes and ears...yes ears! Any and all blast material will find its way into the ear canals.

In order to avoid this I personally use a Nova 3 air feed blast helmet along with a disposable tyvec paper suit.

For the one time backyard user I would suggest you look at using a pressure washer with a sandblasting tip attached to it...works wonders !!

Here is a northern tool video on the pressure washer sandblast attachment.



You will get soaking wet while doing this but there are advantages that make it all worthwhile.

You wont be breathing in any dust because it is all wet and will immediately fall to the ground!

You can use screened blasting sand, not play sand. Play sand from the big box stores is full of larger particles that will clog up the tip!
If using sand (wet), I would recommend a 20/30 grit for the underside of the bus.

But, I would personally recommend using crushed glass instead. It contains practically no free silica, it is very reasonably priced and the crushed glass by itself is safe to dispose of in the trash. Rust under the bus is typically not a hazardous waste so you would be safe in dumping that in the trash to.
If you use crushed glass use either a fine or medium grit.

After you finish blasting you will want to treat the clean raw steel with some sort of rust treatment. My number one choice is OSPHO.

Raw clean steel that has been recently blasted wet or dry will begin to flash rust almost immediately. You do not want to blast then paint without treating as rust WILL begin to form under the paint and you will have a paint failure event sooner or later. OSPHO is cheap so remember an ounce of prevention is worth a pound of cure.

Once you clean, treat and are ready for paint please be sure to use an epoxy primer to seal in the blasted work area. Regular 2k primer will bleed, will allow moisture to penetrate thus creating the opportunity for more rust growth.

I hope you find this info helpful and again please, PLEASE, DO NOT DRY BLAST WITH SAND !!!

Oh yeah I almost forgot, no matter what blasting media you use, be prepared to use quite a bit. On a 30 foot boat, while taking off the antifoul bottom paint I will typically use about 600-700 lbs of sand. ( remember I blast wet not dry!)
I've blasted both wet and dry - wet definitely does have some advantages - with wet, you have no dust - protective clothing can be as little as long sleeves, gloves and a face shield ( rain clothes are a definite help ) - the disadvantages include the amount of sand needed and on larger jobs, what to do with the run off, and as mentioned above, flash rusting when blasting steel - dry blast reduces costs for sand as good sand can be used 2 or 3 times, depending on the surface being blasted - hard surfaces like steel dulls the sand quicker and 2 uses is likely all you can expect - concrete, in most cases allows 3 uses of the sand because of the more resilient surface - run the sand through a suitably sized screen to rid it of unwanted material - dry sanding requires an air fed sandblasting helmet and a charcoal filter for the air supply ( you don't want to be breathing any oil that the compressor might be mixing with the air it sends through the lines ) - the negatives with dry blasting is mostly the dust it creates - it does go everywhere - neighbors will complain about it if they are nearby - ( we were blasting 30 years of paint off a city swimming pool one time - hour after hour after hour, the hypnotic sight of the 1/2 inch wide line made by blasting, and the hissing sound of air in his helmet caused my guy doing the blasting to fall asleep on his feet - lol his arm and hand continued moving, his body was still making it's side to side rocking, but he wasn't advancing - it took minutes to realise something was wrong - shutting off the sand woke him up with a start - lol )
Sleddgracer is offline   Reply With Quote
Old 05-16-2019, 10:30 AM   #5
Skoolie
 
tugboater's Avatar
 
Join Date: Apr 2018
Location: Palmer, AK
Posts: 229
Year: 2004
Coachwork: Thomas
Chassis: Saf T Liner MVP 11 window 32’
Engine: CAT 3126E
Rated Cap: 72
Quote:
Originally Posted by o1marc View Post
I do a lot of sandblasting for my business. For all the small stuff I use a fine grit coal slag (Black Diamond). For lager things my friend does them in his booth at his blast business and uses a 000 sand.
Here's some info that will help you decide which grit to use.

https://www.blackdiamondabrasives.co...ond-coal-slag/
Funny this thread surfaced just as I need to do a little research and make a purchase for a project at work. Have you ever used crushed glass as media?
__________________
One...slow...step...at a time.
tugboater is offline   Reply With Quote
Old 05-16-2019, 10:38 AM   #6
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 5,748
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Quote:
Originally Posted by tugboater View Post
Funny this thread surfaced just as I need to do a little research and make a purchase for a project at work. Have you ever used crushed glass as media?
Not very often, it costs more than the product I need to do the job I want. There are also glass beads that leave a different finish. So the media can also depend on what finish you are wanting. Glass beads are quite a bit more expensive than crushed glass. Grit size is critical as too big will either clog the nozzle or be too big for the blast pressure to even pick up and move through the hose on a low pressure situation.
o1marc is offline   Reply With Quote
Old 05-16-2019, 10:39 AM   #7
Skoolie
 
tugboater's Avatar
 
Join Date: Apr 2018
Location: Palmer, AK
Posts: 229
Year: 2004
Coachwork: Thomas
Chassis: Saf T Liner MVP 11 window 32’
Engine: CAT 3126E
Rated Cap: 72
Quote:
Originally Posted by o1marc View Post
I do a lot of sandblasting for my business. For all the small stuff I use a fine grit coal slag (Black Diamond). For lager things my friend does them in his booth at his blast business and uses a 000 sand.
Here's some info that will help you decide which grit to use.

https://www.blackdiamondabrasives.co...ond-coal-slag/
Funny this thread surfaced just as I need to do a little research and make a purchase for a project at work. Have you ever used crushed glass as media? I've got a project coming up that'll require quite a bit of this type of work and I've been pointed toward crushed glass.
__________________
One...slow...step...at a time.
tugboater is offline   Reply With Quote
Old 05-16-2019, 10:41 AM   #8
Skoolie
 
tugboater's Avatar
 
Join Date: Apr 2018
Location: Palmer, AK
Posts: 229
Year: 2004
Coachwork: Thomas
Chassis: Saf T Liner MVP 11 window 32’
Engine: CAT 3126E
Rated Cap: 72
Quote:
Originally Posted by o1marc View Post
Not very often, it costs more than the product I need to do the job I want. There are also glass beads that leave a different finish. So the media can also depend on what finish you are wanting. Glass beads are quite a bit more expensive than crushed glass. Grit size is critical as too big will either clog the nozzle or be too big for the blast pressure to even pick up and move through the hose on a low pressure situation.
Thanks man..Sorry for the double post...need more coffee
__________________
One...slow...step...at a time.
tugboater is offline   Reply With Quote
Old 05-16-2019, 11:35 AM   #9
Bus Crazy
 
Join Date: Feb 2012
Location: Salt Lake City Utah
Posts: 1,517
Year: 2000
Chassis: Blue Bird
Engine: ISC 8.3
I've done a medium amount of backyard media blasting with the 100 pound Harbor Freight pot. The hood that comes with that thing looks like it came from the costume aisle at the dollar store; I bought a much nicer one from Eastwood. I don't recall what media I'm using since it's been so long since I bought the stuff. Green diamond slag something-or-other, I think.



Tell us more about respiratory protection. When I blast I wear a respirator with P100 filters. Obviously the filters plug up fairly quickly, but would you say this level of protection is much different or worse to the supplied-air type a professional would use?
family wagon is offline   Reply With Quote
Old 05-16-2019, 12:18 PM   #10
Bus Crazy
 
Sleddgracer's Avatar
 
Join Date: Nov 2018
Location: south east BC, close to the Canadian/US border
Posts: 1,008
Chassis: still looking for my bus
Quote:
Originally Posted by family wagon View Post
I've done a medium amount of backyard media blasting with the 100 pound Harbor Freight pot. The hood that comes with that thing looks like it came from the costume aisle at the dollar store; I bought a much nicer one from Eastwood. I don't recall what media I'm using since it's been so long since I bought the stuff. Green diamond slag something-or-other, I think.



Tell us more about respiratory protection. When I blast I wear a respirator with P100 filters. Obviously the filters plug up fairly quickly, but would you say this level of protection is much different or worse to the supplied-air type a professional would use?
workman's compensation specifies air fed helmets and charcoal filters - when I first started sandblasting, our union had to fight to get little charcoal filters that hooked on our belts - guys were coughing up oil and blood before we got the filters - now the requirements have gone from those small filters to large stand alone filters that might put you in mind of a fire hydrant - more recently the rules banned silica sand because of the silica dust - kind of miss it because the silica sand is much sharper than slag and the job went quicker - my strong advise is to rent an air supplied helmet with a proper filter - that dust is nothing to fool around with and can do permanent damage to lungs - I have COPD now, possibly partly caused by sandblasting with the inadequate equipment supplied on the job, working with no protective equipment while using dangerous paints that had no warning labels on them, handling powdered asbestos with no mask or protection of any kind to fix an old furnace in the first house we bought - still finding out via the news that the 1000's and 1000's of pounds of texture I sprayed ( without the use of even a dusk mask on ceilings had asbestos in it, that the 'harmless' latex that we sprayed mask-less outdoors had mercury in it thinking that it had no lead in it - the fact that I've smoked a pack-a-day for 62 years likely doesn't help either - lol - I've already passed my 'best before date' and still pushing - can't imagine what a PITA I would have been had I treated my body and lungs with respect - lol
Sleddgracer is offline   Reply With Quote
Reply

Tags
grit, rust removal, sandblasting, undercarriage

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 06:06 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.