To Drill or Not To Drill?

Purge the tank with nitrogen. Flush the outside in the area of the hole with N₂, too.

What does LynDoor™ Gas Supply charge for "N₂ too" these days? My price book is outdated, I hope you have a currect copy.

$12.69 per therm. In bulk quantities, of course.

Delivery is 10 days, or sooner, normally. Unfortunately, it's on back order right now.

As soon as it becomes available, I would like to order two N2 too to.

You too can order N₂, but too much N₂ can be too bad for you, too.

I may actually begin to put the Vette back together soon, too.

Also.

Thank you for your swift replies.

Would the tank need to be completely purged of air? Also, How many "therms would it take to purge the tank approximately, if I go that way, I would definitely want enough to complete the job. Again, thanks to all for your input.

Newagedave

We'll assume for the moment that you understand "therms. You'll also need to understand the lower explosive limit of your polyester fumes.

I'd say purge the hell out of it, and continue to flush the inside as well as the outside with fresh N₂. It'll take 5,000 "gallons" to start.

Obviously, Tornado's admonition to be sure fresh air is available to the driller is good advice.

Maybe omw7 will do it for you.

If you flush the exterior w/ N₂, wear an air-supplied hood or SCBA. You don't want to suffocate any more than to blow up.

Why do you think there will be sparks? Or even overheating? If you use a new drill at the right speed with the precaution of sending a jet of liquid coolant towards the drill end, then it would seem to stop both sparks and heat. Drills don't produce sparks if they are sharp and turning at the correct speed as per their diameter.

What about the sparks inside the drill motor?

Solved

Don't trust a cold spark-free drill cut. When something goes wrong 2 components of your drilling process can start a fire or ignite an explosion. (very local temperature - call it a hardly noticeable pre- combustion chamber as soon the tank is perforated - or a spark)

When you do it with a full tank, you need less nitrogen?

The nitrogen pushes the oxygen out and no fire or explosion because of the lack of it. Removing one of the 3 ingredients necessary for fire or explosion is enough. What is a BH fitting? In Europe it is hardware for a bra. How big of a diameter you want the hole? You can also cut it with a water beam cutting device.

There is better advise in the posts, but if you follow this one, make sure the resin has no air bubbles in it. (that is oxygen too)

Very nice style to give a thanks to CR4 here. Hope suggestions keep coming and that in the end you'll be safe and well. Let us know, Ky.

Two ideas that pop in mind:

Drill when the tank is full! Where there is Resin there is no air, where there is no air there is no flames.

Fill the tank with water (if possible - not sure with the resin) I think its enough up to the point where you drill! Hope you dont do the top of the tank.

Just a thought

W.

You don't say how high on the tank you want to put the bulkhead fitting but the following method has been used many times in the chemical industry. The higher the fitting, the higher the tank needs to be purged and the more expensive it gets to do.

Use Argon, a inert gas that is much heavier than air and is sometimes used to extinguish fires/flames, to purge your tank. As the Argon is put in the tank it settles at the bottom and the interface of the argon/flammable atmosphere rises up within the tank. Put enough of it in the tank and the tank is completely full of argon. Just make sure you plug off any other openings in the tank below where you are adding the argon or else it could leak out of them.

The argon and the flammable gas mixture don't mix because the argon is inert and the argon's density is much heavier than the flammable gas mixture and makes it sink under the flammable gas mixture.

I have personally used this system on many storage systems and reactors for hot work when it was impossible or too dangerous to remove all materials/vapors to such a degree that it was safe to drill or weld. The only problem is that when you use a LEL gas meter to test the atmosphere the meter will give you a weird reading because they are calibrated using air as the background gas and not argon. One alternative is to take a gas sample in a beaker and stick a long match in the beaker. It the match goes out its argon, if it still burns or flares up you need to add more argon to raise the interface level up higher above where you took your sample from. Yes, there are more scientific methods but this one does the job. Just remember to use appropriate gloves and face shield.

To remove the argon just refill the tank or open a bottom drain on the tank. Remember though, argon does not support life and creates an atmosphere that does not support life. DON'T BREATH IT!

Good Luck, Old Salt

Use dry ice in the bottom of tank after cleaning, leave over night. The co2 that evaporates from the dry ice will purge the tank. Then weld a thread o let on the tank. Hot tap thru a nipple and full port ball valve. Be sure to verify the o2 and explosive level in the tank.

I have used Argon several times to weld repair the necks of steel gerry cans that are used to store petrol or distillate.............I almost fill the can with water (just below the weld area) and run Argon through it for several minutes, then carry out the repair leaving the Argon turned on during the welding repair.

I am a newbie here and just wanna say Hi to everyone. I am Daniel from Pennsylvania, US.


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I do not know if this is feasible on your tank and in the location you work. We use water jet cutting on subsea structures where high levels of hydrocarbons might be present. If a local contractor is tooled up for it it is a lot cheaper and faster than purging a large tank. It works well on hard surfaces such as steel.

There are also special techniques (hot-tapping) for welding on a flange and drilling the branch hole (T D Williamson do this) on gas or oil lines, both onshore and offshore, but these tend to be used only as a last resort as they have to be carefully managed.

Just thinking off of the top of my head:

Filling the tank with water is going to take two days (5,000 gallons is a lot of water) then you have contaminated water.... 5,000 gallons of it.... when you finish. Obviously you can't just flush that into the sewer.... which means it's going to need to be treated to remove the Poly Resin. And the correct procedure for that would be...??? (Clearly beyond my expertise!).

Don't mean to put a knot in your plan, but.... there it is.

Unless you only need to fill it to level X, which would then be less than the whole 5,000 gallons, but then you are still stuck with that amount of contaminated water....

Sorry for coming in a bit late.

That water waste and the use of N2 are both overkill, I think. Here is what I would do:

If one can get to the inside of the tank one could cover the area that is to be drilled with a rubber matt. (or other suitable material) Even a spray on foam would work. If I am getting this right, t is to seal the inner tank from the heat (possibly no sparks) off the drill bit isn't it?

This foam or thick rubber matted material would be glued to the area and could be drilled from the out side with out ever causing sparks or heat in the critical interfaces of poly resin and atmospheric ambient air. The drill bit should never penetrate the "insulation" on the inside of the tank.

Why seal off the whole tank if you can keep the to be isolated area small. Any size you like really. After all is done remove insulation and bolt whatever needs bolting. That's what I would do if I had someone to bounce this idea off, just to double check.

Nothing wrong with it if I can visualize the situation correctly.

Hope all works out for the OP.

Happy drilling, Ky.

Why not glue the now well known jar on the inside? At least that should have been an other positive contribution. (I refer to a recent publication)

As long as there is isolation anything goes. Resent publication?

Location: E WPB, is that East West Palm Beach?

Near the Cuban coffee stand(s).

One thing no one has considered is that if the material is that flamable, the sparks created by the brushes of the drill might set it off. Eliminate all of that by punching a hole in the metal with a standard punch covered with cloth/plastic/rubber etc. to prevent sparks from striking it with a hammer (or use a brass hammer) and then using a Greenlee punch to finish the opening. I assume you can get to the inside of the vessel to fit the punch since you want to install a fitting.

heard the echo. Same

"Any suggestions as to how I can drill a hole for my BH fitting,"

"having access to a 'Think Tank'",

Is that the same thing?

Too.

Two?

I am a newbie here and just wanna say Hi to everyone. I am Daniel from Pennsylvania, US.


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Not wanting to put the blanket on some of the ideas offered, but the following article about a recent fatal accident emphasizes the need to only use procedures that have been carefully thought out and have undergone a risk analysis. Those that have had a careful risk analysis, are well thought out, have an extremely low level of risk and have a proven track record of safe completions are the only ones that should ever be considered for such an operation as you are contemplating.

http://www.wtop.com/?nid=111&sid=2111704

Regretfully, one person was killed and another seriously injured in this incident. Having done numerous accident investigations in the chemical industry, the most frequent cause is human carelessness and not doing a risk analysis before attempting the task. This can be confirmed by reading some of the investigations from the "Chemical Safety Board" and the "National Transportation Safety Board". Both of them are available on the internet and make very serious and alarming reading.

One life is too much to risk! Odds of a million to one are great unless you are the one.

Old Salt

I recently dropped a lit match into an empty fuel tank, forgetting of the residue, the hairs on my hands haven't been the same since...

Sounds like when I was siphoning out the gas tank into a 5 gallon jug, got distracted, and found there was a lot more than 5 gallons in the tank. Spread cat litter on it to soak it up, swept it into a pile and lit it. DON'T DO THIS AT HOME ANYWHERE, EVER!

Another bit of advise from my past. Don't use a cutting torch on transmission x member while siphoning gas. (Just in case someone asks about it)

Her's a real story Bob.

The son of the business owner had installed a more powerful exhaust fan for the paint boot. Hood and all. It was about as unbalanced as he was. Shaking like a fit on steroids.

I told him that he had to do something about it. He didn't, until the pop rivets had come lose and the noise was starting to get to the people in the masks. He drilled them out and had to drill new holes. I was not present but he did it during full operation flow. The masked blokes didn't even know he was doing it. The show must go on, whatever the cost.

All I heard was the siren and the security doors closing. It was in a factory manufacturing picture frame molds and we must have had a million km's of profiles, all standing upright. Dry timber and partly coated with highly flammable lacquers. The security system saved the day and the automatic shut down and the flooding of the sprayboot with an inert gas kept the damage at a minimum. The draft had sucked the flames away from him so he was OK.

He took a week off (after I spoke to his Dad) but was back at work, to my frustration. He came back just after we had finished installing it appropriately.

The bosses son. I wonder if he is still alive?

He is probably running the company, and hiring and firing people like you and me.