Pre powder-coating prep? Blasting?

[julianf]

Ive just acquired a scrap domestic oven which i intend to rob the bits from to build a small powder oven (i only do small parts anyway).

Ill want to coat both steel and alloy parts. Both will be new. The alloy comes to me with the protective film still applied, and the steel generally with a bit of oil and a tiny bit of surface rust.


Do i need blasting? If so, with what? And can i use the same media for both?


Is there some sort of chemical etch that i can dip the alloy into briefly? I mean, caustic soda eats it quick enough that im sure that would key it without blasting.

And the steel?


I have a couple of 3hp compressors and one of those blast pots, that ive never upgraded the valve on, but no cabinet - theyre not big money to buy, but its more the space that these things take up.

But.. my buyers are fussy, so the cosmetics have got to be right, or not at all.

Thank you.

 

[brightspark]

depending on where u use it have u a cabinet with extraction or just open blasting

 

[AndersK]

Light blasting on hot galv or alloy is what the professionals do, at least those who cares about their customers.

 

[julianf]

depending on where u use it have u a cabinet with extraction or just open blasting

No cab. Indeed, I've never used the pressure pot that I purchased about 2 years ago! (It was just £25)

If I need to blast I'll buy a cab and sort out the valve on the pressure pot.

Again it's not the money but the space, but if that is the way to do it, then that's what I need to do.

If I'm using a cab, can I use the same media for the steel parts as for the alloy, or will I get some sort of cross contamination going on?

And will I need to do some sort of wash after, or just a blast over with clean air?


Again, this is work stuff, not one-off personal, so I need a quick, easy and consistent process.

Thank you

 

[brightspark]

i use kiln dried sand. just use it the once and realy good on ally and steel

 

[julianf]

If I'm doing total loss, then I guess I don't need a cabinet.

I don't know if my compressors will be good for my air fed mask at the same time as the pot though.

I assume sand in a cabinet with adequate extraction is an acceptable process?

I also have next to no idea how long a bag of sand lasts (or how long a bit of string is!)

The steel box I'll be blasting is 17" long by 7 by 3. It's basically a steel bowl with a lip.

I have a pair of 3hp 1ph compressors and one of those Chinese blast pots (unmodified).

In your experience, again, very roughly, are we talking a bag of sand to do 3 boxes, 10 boxes, or 50 boxes? Inside and out, new mild steel.

I'm just trying to get a feel for what's involved. I don't need precision quantities, I'm just wondering if you could give me a rough idea of how far 25kg will take me?

Thank you.

 

[brightspark]

a light dusting off with sand a 25kg bag will go a fair way using a good pressure .you can use it twice if u sieve it . anymore than that and u just end up hurtling dust about . you wont be able to use an airfed mask and run the pot at the same time . just buy a bag and give it a go

 

[optima21]

i use kiln dried sand. just use it the once and realy good on ally and steel

you know its banned for blasting commercially due to Health and safety issues, might have been fine to do years ago but not anymore (like smoking in pubs was fine too)

https://www.hse.gov.uk/pubns/guidance/cn7.pdf

if you're only doing small items, you can get small benchtop blasting cabinets which work well with a few tweaks

benchtop blasting cabinet modifications.

I've had one of these http://www.ebay.co.uk/itm/200472037005 for a while now so thought I'd best start tweaking it so I can use it for blasting small parts. for many years Ive been using one of these blast guns (originally from Anglo Scot Abrasives)...

www.mig-welding.co.uk

 

[brightspark]

you know its banned for blasting commercially due to Health and safety issues, might have been fine to do years ago but not anymore (like smoking in pubs was fine too)

https://www.hse.gov.uk/pubns/guidance/cn7.pdf

if you're only doing small items, you can get small benchtop blasting cabinets which work well with a few tweaks

benchtop blasting cabinet modifications.

I've had one of these http://www.ebay.co.uk/itm/200472037005 for a while now so thought I'd best start tweaking it so I can use it for blasting small parts. for many years Ive been using one of these blast guns (originally from Anglo Scot Abrasives)...

www.mig-welding.co.uk

pretty much useless and slow using a suction gun apart from verry small parts and your in no great rush

 

[Dcal]

If I'm doing total loss, then I guess I don't need a cabinet.

I don't know if my compressors will be good for my air fed mask at the same time as the pot though.

I assume sand in a cabinet with adequate extraction is an acceptable process?

I also have next to no idea how long a bag of sand lasts (or how long a bit of string is!)

The steel box I'll be blasting is 17" long by 7 by 3. It's basically a steel bowl with a lip.

I have a pair of 3hp 1ph compressors and one of those Chinese blast pots (unmodified).

In your experience, again, very roughly, are we talking a bag of sand to do 3 boxes, 10 boxes, or 50 boxes? Inside and out, new mild steel.

I'm just trying to get a feel for what's involved. I don't need precision quantities, I'm just wondering if you could give me a rough idea of how far 25kg will take me?

Thank you.

I use supafine Jblast in a pressure pot piped into a blast cabinet and reuse the grit until it's mostly dust.
Jblast is cheap enough if you buy by the ton (or half ton) to not bother with sand and it's inherent risks.

I use an air fed half mask as it uses far less air, I also have a 4 inch wood chip type extractor plumbed in, as it gets rid of most of the dust so you have a chance of seeing inside the cabinet.
A bag of Jblast lasts a fair while and you probably want to use it a few times on steel so it is finer by the time you get to using it on alloy
I think you will get 6 to 10 boxes done out of a fill of the pot.

Are both parts to be painted? If so I wouldn’t worry about cross contamination.
Just blow the parts to remove dust.
A rag or paper will get shredded if you try to clean blasted parts by that method and will create a mess, it’s unnecessary anyway.

I free blast as well but only when I can’t get the part in the cabinet.
I use the pot in the cabinet far more as it's always ready to go and so quick and easy with no mess to clean up.

Link to my cabinet mods, you probably have already seen the media valve mods.

Cheap Blasting Cabinet and Pressure Pot Upgrades

I bought a blasting cabinet on the forum over 3 years ago and have been using it since. I already had one of the Clarke 10 gal pressure pots so I ended up marrying the two together. They work but not great and have some major flaws so I've been modifying them over the years and thought it was...

www.mig-welding.co.uk

 

[julianf]

a light dusting off with sand a 25kg bag will go a fair way using a good pressure .you can use it twice if u sieve it . anymore than that and u just end up hurtling dust about . you wont be able to use an airfed mask and run the pot at the same time . just buy a bag and give it a go

Thank you. I'll get a sack next time I'm out.

I've stuffed up with lung stuff in the past - I was in hospital having lung X rays just as covid was dawning, hence being quite cautious now. Once bitten, twice shy and all that!

 

[brightspark]

i only use the sand in the cabinet as it has a 4inch woodchip extracta fitted to outside and can suck more air out than the comp can shove in i use it open blasting but have an airfed blast helmet and comp big enough to run both

 

[Parm]

Thank you. I'll get a sack next time I'm out.

I've stuffed up with lung stuff in the past - I was in hospital having lung X rays just as covid was dawning, hence being quite cautious now. Once bitten, twice shy and all that!

In that case what ever you do don’t get a bag of sand

Do it safely or don’t bother at all

 

[julianf]

I use supafine Jblast in a pressure pot piped into a blast cabinet and reuse the grit until it's mostly dust.
Jblast is cheap enough if you buy by the ton (or half ton) to not bother with sand and it's inherent risks.

I use an air fed half mask as it uses far less air, I also have a 4 inch wood chip type extractor plumbed in, as it gets rid of most of the dust so you have a chance of seeing inside the cabinet.
A bag of Jblast lasts a fair while and you probably want to use it a few times on steel so it is finer by the time you get to using it on alloy
I think you will get 6 to 10 boxes done out of a fill of the pot.

Are both parts to be painted? If so I wouldn’t worry about cross contamination.
Just blow the parts to remove dust.
A rag or paper will get shredded if you try to clean blasted parts by that method and will create a mess, it’s unnecessary anyway.

I free blast as well but only when I can’t get the part in the cabinet.
I use the pot in the cabinet far more as it's always ready to go and so quick and easy with no mess to clean up.

Link to my cabinet mods, you probably have already seen the media valve mods.

Cheap Blasting Cabinet and Pressure Pot Upgrades

I bought a blasting cabinet on the forum over 3 years ago and have been using it since. I already had one of the Clarke 10 gal pressure pots so I ended up marrying the two together. They work but not great and have some major flaws so I've been modifying them over the years and thought it was...

www.mig-welding.co.uk

Both steel and alloy are to be powered (not painted).

I have a 100mm wood chip extractor currently, so could easily use that, or hook up a bouncy castle blower somehow.

i only use the sand in the cabinet as it has a 4inch woodchip extracta fitted to outside and can suck more air out than the comp can shove in i use it open blasting but have an airfed blast helmet and comp big enough to run both

It seems I should probably give it a quick test and then start looking at cabinets. Thank you.

 

[brightspark]

Both steel and alloy are to be powered (not painted).

I have a 100mm wood chip extractor currently, so could easily use that, or hook up a bouncy castle blower somehow.



It seems I should probably give it a quick test and then start looking at cabinets. Thank you.

i wear a mask at work for any dust roofing insulation or cutting kingspan as it makes me ill and nearly choke so any dust of sand id soon know about it

 

[julianf]

These look just as good/bad as any of them, right?

-

MAXBLAST Sandblasting Cabinet 220L

Sand Blasting Cabinet The 220L heavy-duty, abrasive sandblasting cabinet is the ideal solution to your sandblasting needs. The sandblasting station is easy to operate, portable and offers a safe and secure environment; ready for you to use with your choice of abrasive media. The sandblaster is...

www.monstershop.co.uk

Theres one on fb market place near me for about half new price.

(im sure the last time i looked, these things were about £140 new anyway, and now they all seem to be over £200!)

 

[Dcal]

If it's big enough for your needs it will be fine.
They all need mods to work well but with mods, (extraction, rigged for a pressure pot and extra light ) they are a very useful tool.
I wouldn't be without mine.