Weld prep sequence

[53Sparky]

Hi guys - Just joined the GJ recently, although I've been on the HAMB & a couple of other forums too for several years. So not a NEWB, but I'm a NEWB here.

For the last 25 years I've built everything I needed out of wood up until last year when I got started with metalwork.

I'm wondering what your preferred sequence of work is when working with steel, especially in the prep stages before you weld.

So far my process has been:

Draw in CAD
Purchase
Clean
Cut
Clean/grind weld areas
Weld
Prime
Paint

Is there any argument for changing the sequence of cleaning & cutting? I'm just a hack with no real world metal shop experience. What's the standard procedure in a professional shop?

Thanks in advance!

53Sparky!

 

[jimgood]

That's actually a great question, to which I have no reply since I'm a hack welder. But I'd like to hear from the pros.

I'd also like to hear how you plan for weld distortion. Does it affect your measurements? Gaps? Arrangement of parts prior to welding?

 

[Thumper68]

Hi guys - Just joined the GJ recently, although I've been on the HAMB & a couple of other forums too for several years. So not a NEWB, but I'm a NEWB here.

For the last 25 years I've built everything I needed out of wood up until last year when I got started with metalwork.

I'm wondering what your preferred sequence of work is when working with steel, especially in the prep stages before you weld.

So far my process has been:

Draw in CAD
Purchase
Clean
Cut
Clean/grind weld areas
Weld
Prime
Paint

Is there any argument for changing the sequence of cleaning & cutting? I'm just a hack with no real world metal shop experience. What's the standard procedure in a professional shop?

Thanks in advance!

53Sparky!

There is no reason to clean before cutting unless the steel (or other metal) is very nasty, so I would eliminate that step.

Then you can add in dressing the welds before prime depending on what finish profile you are going for.

That's actually a great question, to which I have no reply since I'm a hack welder. But I'd like to hear from the pros.

I'd also like to hear how you plan for weld distortion. Does it affect your measurements? Gaps? Arrangement of parts prior to welding?

This is something that can really only be learned from practice, but in general material will pull towards the weld, so you need to plan out the weld to account for this and make sure you have good tacks.

How much it moves has a lot of variables depending on weld process, material thickness, material type, clamping, bead size, and lots of other variables.

 

[sqznby]

Your list looks good to me.

You could eliminate the first cleaning process since you will be cleaning and prepping before welding.

Weld distortion can be avoided by placement of tacks and sequence in your welding process as well as the use of many clamps.
Gaps can be worked into the measurements depending on the situation. Typically you would bevel the weld joint so gaps may not be necessary.

This is all dependent on each situation.
Also dependent on each weldor/fabricators.

 

[zkling]

I have two types of projects.

1) Personal, friendly and I'd lump some repair projects in this. "stock selection" = dig through scrap pile, if I planned on using 1" 125 and have a bit of 1.5" 125 on hand, well guess what gets used?

2) More involved projects, especially for others, a drawing gets made, cut list created and BOM produced.

Metal working is, no can, be less step by step invloved than some of those wood projects that require 65 pieces to be glued and clamped all at once.

Starting EVERY project with a drawing, would be a pain and take alot of the enjoyment out of it IMHO. Then again I say that knowing full well I struggle with mirror parts.

In a professional shop, well depends on how professional you want to get. Engineering department approval, quality approval, submit to shop for approval. Make a change, produce a ECR, submit to purchasing with a BOM, correct BOM, update drawing, back for approval, and on and on and on....

From your list, you might want to add a prep before painting, some welding operations and wires will hinder paint adhesion and or aesthetics.

 

[Bondo]

Draw in CAD
Purchase
Clean
Cut
Clean/grind weld areas
Weld
Prime
Paint

Ayuh,.... I get a vision of what I need, sometimes it'll get drawn out on a scrap of paper, most times not,.....

Then I go dumpster divin' to find some matrial I can make work,....
Once I've dug up what I need, I go ta Buildin',....

If I get 'round to primin', 'n paintin', that's a Good thing, if it don't,.. Oh well,...

 

[Thumper68]

I have two types of projects.

1) Personal, friendly and I'd lump some repair projects in this. "stock selection" = dig through scrap pile, if I planned on using 1" 125 and have a bit of 1.5" 125 on hand, well guess what gets used?2) More involved projects, especially for others, a drawing gets made, cut list created and BOM produced.

Metal working is, no can, be less step by step invloved than some of those wood projects that require 65 pieces to be glued and clamped all at once.

Starting EVERY project with a drawing, would be a pain and take alot of the enjoyment out of it IMHO. Then again I say that knowing full well I struggle with mirror parts.

In a professional shop, well depends on how professional you want to get. Engineering department approval, quality approval, submit to shop for approval. Make a change, produce a ECR, submit to purchasing with a BOM, correct BOM, update drawing, back for approval, and on and on and on....

From your list, you might want to add a prep before painting, some welding operations and wires will hinder paint adhesion and or aesthetics.

This is so very true, Look at my bumper build video's I state several times that I was building them on the fly from a picture in my head, nothing drawn out, not even a rough sketch. I just knew the look I was going for and built them.

For materials I used a combination of stuff I had on hand and drops of 3/16" plate that I picked up from my supplier.

 

[Milton Shaw]

Depending on the project, you usually would have some holes to drill or punch and debur. Also some straightening may be necessary after welding depending on what the project is. Also a check to see if it fits, depending on the project such as a bumper/winch bracket etc. It looks much nicer it its fixed/adjusted before you paint/finish it.

 

[ilovevocs]

I feel like i do allot of process design with welding. What needs braced/ fixtured / clamped... What dimensions are critical and what are not. What is my weld sequence to prevent distortion... The process isn't just cut and weld per dimensioned drawing IMHO.

 

[INSP380]

Add fit, tack, check ( meaning MEASURE ) then weld, MEASURE, straighten, .....


Steve

 

[brownbagg]

and all just do is hit the circuit breaker to the welding machine

 

[mikhett]

Ive been a HAMB member since 2005.When I mig weld patch panels on old cars .I use a tight fit-up (no-gap)and stretch the haz area with Hammer on dolly hits working only the HAZ area.Check out MP&C on here Hes the best!!!

 

[ZRX61]

A lot of the time I don't even bother with a sketch, let alone that CAD malarky. I know what it's supposed to look like & how big, so I just cut the metal & weld it together.
I've been known to build metal frames that have parallel tubes & the space between them is 3 1/2in because that's how wide the 2x4 I stuck in the gap is.
Case in point: built a custom California King bed frame out of 2x2, 1x1 & 1x2 square tubing. The height was decided by measuring from my **** to the ground & subtracting the thickness of the mattress & box spring. The two top perimeter frames are 3 1/2in apart...

 

[yaidunno]

In regards to the gaps, generally speaking, a tight fit will yield less distortion of the work piece. There will always be some movement, but controlling it, and using it to your advantage take time to learn. Ridged fixturing will also help to keep parts true when welding.

Your process is certainly along the lines of how things are done chronologically, with the exception of cleaning the material prior to cutting, as somebody else mentioned. There are obviously little details in each step, but generally speaking, I don't see that you're missing anything obvious.

 

[EdT]

Cad is a wonderful tool especially if you have to modify a design or make more over a period of time. It's nice to have a permanent record of the part in case you have to make another some day (assuming you can find the file again). For simple stuff I find a simple mental sketch or sketch on paper is a lot faster and less time is spent trying to get the computer to work and more time can be spent actually doing the job. I you know you need an 18" piece of 2" square tubing, just go cut one off, having a CAD drawing with one or two dimensions on it isn't going to make it any easier. Of course, you may be one of the rare individuals who can design and detail an complete front suspension in a lunch hour in which case, CAD away.

 

[airrj]

I like your preferred sequence. I use that as my base sequence and adapt for the particular project as needed, however I thought about it enough to write it down before.

By adapting I use the complete list for larger projects and for smaller projects I will for example switch CAD to Sharpie sketch on the weld bench. As for the clean/cut/clean and grind I find that I like this order often. If the material is new from the mill my first clean is a quick wipe with acetone. This makes marking and handling quicker. And if the piece is a nasty hunk from the scrap pile the clean will be to knock off the mud/grease and then wire wheel the rust and chunks off of it.

Lastly, depending on the project I find myself skipping most of the paint prep and just a quick acetone wipe and then some $0.99 Wal-Mart black rattle can lacquer paint on it. For stuff that is just a tool to be beaten up this works great. And for the front range area heavy duty prep/prime/paint isn't needed for rust prevention with the low humidity I have found. And for items that need a quality finish I do step up my process to match the outcome expected.

 

[Capt Chrysler]

A lot of the time I don't even bother with a sketch, let alone that CAD malarky. I know what it's supposed to look like & how big, so I just cut the metal & weld it together.
I've been known to build metal frames that have parallel tubes & the space between them is 3 1/2in because that's how wide the 2x4 I stuck in the gap is.
Case in point: built a custom California King bed frame out of 2x2, 1x1 & 1x2 square tubing. The height was decided by measuring from my **** to the ground & subtracting the thickness of the mattress & box spring. The two top perimeter frames are 3 1/2in apart...

Capt. Chrysler

 

[53Sparky]

There is no reason to clean before cutting unless the steel (or other metal) is very nasty, so I would eliminate that step.

Thanks, I'll skip this step unless it's exceptionally dirty when I get it.

I have two types of projects.
1) Personal, friendly and I'd lump some repair projects in this. "stock selection" = dig through scrap pile, if I planned on using 1" 125 and have a bit of 1.5" 125 on hand, well guess what gets used?
2) More involved projects, especially for others, a drawing gets made, cut list created and BOM produced.
Starting EVERY project with a drawing, would be a pain and take alot of the enjoyment out of it IMHO. Then again I say that knowing full well I struggle with mirror parts.

Ayuh,.... I get a vision of what I need, sometimes it'll get drawn out on a scrap of paper, most times not,.....
Then I go dumpster divin' to find some matrial I can make work,....
Once I've dug up what I need, I go ta Buildin',....
If I get 'round to primin', 'n paintin', that's a Good thing, if it don't,.. Oh well,...

Right. Of course there's a place for the down n dirty welding task that doesn't require CAD. I guess I was really asking more about the larger scale stuff for clients or long term use where you're not just sticking two sticks together

The height was decided by measuring from my **** to the ground & subtracting the thickness of the mattress & box spring...

That's Funny right thurrr

CAD is a wonderful tool especially if you have to modify a design or make more over a period of time. It's nice to have a permanent record of the part in case you have to make another some day (assuming you can find the file again). For simple stuff I find a simple mental sketch or sketch on paper is a lot faster and less time is spent trying to get the computer to work and more time can be spent actually doing the job. I you know you need an 18" piece of 2" square tubing, just go cut one off, having a CAD drawing with one or two dimensions on it isn't going to make it any easier. Of course, you may be one of the rare individuals who can design and detail an complete front suspension in a lunch hour in which case, CAD away.

CAD comes pretty easy for me. I also find it helpful to do the process once in virtual space because I often find a better way to build something when I see it in front of me. That saves me cutting apart something that I built incorrectly.

By adapting I use the complete list for larger projects and for smaller projects I will for example switch CAD to Sharpie sketch on the weld bench. As for the clean/cut/clean and grind I find that I like this order often. If the material is new from the mill my first clean is a quick wipe with acetone. This makes marking and handling quicker. And if the piece is a nasty hunk from the scrap pile the clean will be to knock off the mud/grease and then wire wheel the rust and chunks off of it.

Good advice here



Thanks, guys!

Preferred metal prep chemical?

Depending on the application I've been using Simple Green, Easy Off, or Acetone. Is there a better option?

I know Brake Cleaner is a no go.

53Sparky

 

[INSP380]

We use a Eco version of Simple Green, followed by Acetone. We clean everything in Acetone, Tig rod even. On that note, we also don't cross contaminate our work by mixing grinding wheels, wire wheels and HS carbide wheels when switching materials with different P numbers. How clean are your gloves? Overkill for most at home. but details count.

Steve