Welding Tips and Tricks

Hi guys, so I have an odd question. I am building my new man cave/shed/garage/workshop what ever you call it and I will be pouring a new concrete slab. I am just wondering what surface will stand up to welding. Concrete polishing, sealed concrete?
I am over thinking this probably so I thought I would ask you guys. I wanted it to be smooth as so I can roll stuff around in there.

Cosi,
First off let me state that I'm no concrete expert, but there's a few things I've learned over the years.

If you make it super smooth finish it will be very slippery when it's wet. If you're going to use it for strictly welding and fab stuff I would stay away from a very smooth finish as it's not really needed. Don't make it so rough that it's hard to sweep up grinding dust. Make sure you add enough control joints in it keep the cracks where you want them, all concrete cracks, period. Silicone works great in your control joints and you can strike it like a mortar joint with foam pipe insulation for a clean look.

I would make my floor as level as possible which will aid in getting things fitted up easier. If you're going to have drains in the floor, make the floor slope as narrow as possible so you don't eat up all your level floor space.

Don't cut with a O/A torch or a plasma cutter near the floor, concrete is porous and holds moisture which turns to steam and will pop out chunks of it. Even grinding can make enough heat on new concrete to flake up the surface.

Those are the only suggestions I have for now.

Len

What I like is a smooth finish and then painted with the good stuff. When sealed like this its easy to sweep or hose out, you don't get cement dust/grit hanging around for ever and items left on the floor won't rust as easily. Degreasing is much easier to do as well.
Ditto for level and hot work.

In my new workshop, I went to a lot of trouble to get the floor really level.

We lasered to levels right around the perimeter before the slab was poured, and got the guys to work very carefully to all of the marks. This makes it so easy to layout a job, tack it up, and know that everything was square. Sometimes I use large H beams (RSJ's) to setup from. I can place these anywhere on the floor and know they are all parallel, and start fabricating on top of these, knowing there are no twists, etc.

I got the floor laid in one single slab with no troweled expansion joints, meaning it's dead flat. Then I used a concrete saw to cut in the expansion joints, and filled them flush with gap filler, before painting the entire area with a concrete paint. It's durable, easy to sweep and keep clean, can be re-painted if required, and flat. I've also got several lathes, milling machines etc in the same area, so the level surface was a double bonus.

Hope this helps some with ideas

Trev

What kind of paint are you guys using? We sealed our whole shop floor with an epoxy. It works great everywhere but the welding room. The epoxy melted and burned quickly from any sparks that touched it. We ended up putting down aluminum diamond plate and welding the corner together.
Im not sure what brand of sealer we used.

I just use a good quality paving/patio paint, just roll it on with two coats initially. It does wear off with abuse but generally stands up surprisingly well to hot work work as long as you don't oxy cut right on it. I've never had it peal and I will re-coat every 5 years or so. Degreasers doesn't seem to bother it either.

Some floor paint gets quite slippery to walk on if wet - I've used ships deck paint ( the sort with fine sand in ) think it was made by international - likely very expensive if out of your own pocket - but held up well.

I set up a new workshop about three years ago, with a concrete floor. The concrete is about 150mm thick, 50% up on a usual floor slab, and the centre and area in front of the roller door are level, but it tapers way at the sides.

I haven't done anything special to the surface, but the locals I have asked say not to put anything on it. Sometimes I get a bit of concrete dust when I sweep it (I sweep daily, or after each job: I hate working in the grit).

Now, by chance, my level area is large enough for the work I do, some trusses, frames, etc, and it certainly accommodates my welding table (on wheels -- great idea, I have found).

But I have been "lectured", warned, even, about welding on concrete: the moisture in the concrete can be heated to steam, and little explosions might result. While I haven't experienced anything like this, it might be something to get advice on.

I must say, though, if I can get the work up to bench height, even supported over a web of trestles, etc, I find I enjoy the job a bit more. (I have benches around the perimeter of the workshop at exactly the same height as the welding table, and steel over a few metres in length can be supported at each end, with trestles for other points of support. With the roller door up, and this bench - welding table - trestle arrangement I have been able to work at bench height on step stringers some 8 metres in length, for example.

AnvilJack,

If you're torch-cutting a few inches above the floor with the dross aimed down, or welding directly on the surface, you will have "spalling", which is the explosive disassociation of H2O from the concrete. Epoxy coatings will not prevent this.

If you work from horses, tables, stands, etc. that keep you off the surface, this is a non-issue. I'd LOVE to work on a coated surface, where everything rolls smoothly and everything sweeps up clean. Slag, spatter, and dross will slowly erode an epoxy finish, but, so what? Recoat every five years like any other heavy-use surface and call it good.

Steve S

Anviljack and Trev - It sounds like you guys did some great work on your concrete decks! Really well thought out! For me, I like just about everything on rollers so I can move it around. I like a nice, heavy, layout table. In addition, I like to have at least two table 3' X 3', which are on rollers, and have height adjustment. If I am fabbing something that is very long, I can put my 3' X 3' tables under the outer edges, exactly where I need them, and most importantly, use the height adjustment to level them. I also like to have a lot of smaller, single leg adjustable stands. But, for any of this wonderful roller stuff to work, I need a nice concrete deck! Got to pay attention to what is going on in the base! It IS all about the base!

Boomer63, it sounds like I would love your shop.

Rolling tables and stands are just so useful.

I have visited some shops to pick up materials, etc, and have felt positively disappointed to see the fixed tables some people weld on. I'm sure they manage, and I keep quiet about the matter, but, to me, "it just doesn't seem right". It's like these blokes are missing out. Ah well.

Thanks, AnvilJack! I like my fixtures movable and height adjustable. I am sorry to say, I don't currently have a shop! Well, I have a shop in the sense that I teach welding at a college in Indiana.
Gary

I have read and re-read the replies on here

It seems I will be going for the 32mpa (I think that's right and it's probably overkill) slab as it isn't that much different in cost apparently. It will be 150mm thick and it will be poured in 1 go with no expansion joints and laser leveled. The engineer has stated I will need 14 bloody piers at 4 metres deep as there is a main sewer line 2.6 metres deep and the piers need to be deeper than 2.6 and it's soft clay down there. The expansion joints will be cut in down the middle and filled with the glue stuff, yes it's a technical term. Once dried it ill be painted with some tough patio/driveway paint.

Coldman, any idea what the brand was of the paint you used as it sounds like you recommend it.

Not sure if I should tell the concreter to set a fall in it so if I wash out the workshop the water will not sit there but head towards the drain at the front of the slab.

Don't forget I am downunder in oz. I used Taubman's heavy duty paving paint.

Sorry Cosi I led you astray. The paint I used was Berger Jet Dry paving paint.

Coldman wrote:Sorry Cosi I led you astray. The paint I used was Berger Jet Dry paving paint.

Cool. Thanks for that.

I am in Sydney

I spoke to the concreter and he says he can give it a burnished finish and a clear seal, or just smooth it all perfectly and then paint it.

Not sure if I want the burn/polish and then seal or just paint. oh boy! The choice is keeping me awake

If he polishes it you will slip and slide every time it gets dusty or wet. Even just humid wet doesn't have to be soaked to be slick. If he just bull floats it when it's a little dry it will leave a smooth but sandpaper like finnish. This will take the road grade paint really well and you will end up with a very smooth top that will hold up well.

Poland308 wrote:If he polishes it you will slip and slide every time it gets dusty or wet. Even just humid wet doesn't have to be soaked to be slick. If he just bull floats it when it's a little dry it will leave a smooth but sandpaper like finnish. This will take the road grade paint really well and you will end up with a very smooth top that will hold up well.

On my shop floor that's what I did - bull float only, but no paint.

Same for the small extention I just added (20'x10').

I've been on floors that are too well finished, even a little snow on the boots and about kill yourself.

cosi wrote:I have read and re-read the replies on here

It seems I will be going for the 32mpa (I think that's right and it's probably overkill) slab as it isn't that much different in cost apparently. It will be 150mm thick and it will be poured in 1 go with no expansion joints and laser leveled. The engineer has stated I will need 14 bloody piers at 4 metres deep as there is a main sewer line 2.6 metres deep and the piers need to be deeper than 2.6 and it's soft clay down there. The expansion joints will be cut in down the middle and filled with the glue stuff, yes it's a technical term. Once dried it ill be painted with some tough patio/driveway paint.

Coldman, any idea what the brand was of the paint you used as it sounds like you recommend it.

Not sure if I should tell the concreter to set a fall in it so if I wash out the workshop the water will not sit there but head towards the drain at the front of the slab.

32mpa is good, gives a good finish but 150mm with all those piers? Yikes! That does sound like over-kill, a raft slab with beams not good enough? What is the floor area. I did my 39m2 garage floor 10 years ago without expansion joints and a helicopter finish. It's my workshop and so far all good and not slippery.

i dont know about for welding but my shop has a polished floor... big mistake... if its raining or especially snowing when i walk in the door im confronted with the slickest surface and have almost busted my axxx several times. i have had this floor for 15 years and dont see where my welding has any effect.