Bought some new down tube decals for my Carlton. They are the stick on ones, and I believe they are supposed to be clear coated. I don't intend to do anything else other than touch up the paint in places. What should I use -- looking for a rattle can product? Maybe just clear coat the down tube?

There's a Humbrol product that was being complimented on here a month or 3 ago. Can be put on with a sponge I seem to remember.

Edit:
UK Ebay, Must be in the US too

That looks like a good option. The video I found shows it being sprayed on with an airbrush. Maybe I could get a new tool out of this...

This stuff works very well.

Spray Max 2k High Gloss Clearcoat aerosol

Bookmark, I've wondered this too; I still have helicopter tape which works okay but if the spray works too; that seems like it would be easier and less noticeable. The spray is $24 which isn't cheap but maybe workable in the long run. Most home goods stores seem to have a form of a clear-coat aerosol.

I have not tried the Spray max 2K (meaning 2-part or a catalyzed resin so WEAR PROTECTION!) but did try a similar product from Upol that was similarly expensive and had the same sort of internal "capsule" of catalyzer that had to be broken and mixed inside of the aerosol can. With all that I was unimpressed with the results, but YRMV.
For my money I have had the best results with the strangely named clear ENAMEL from Rustoleum, no idea what makes this an enamel but the coating has been very reliably smooth and so far caused no reactions (lifting or crinkly "peel") on color coats (which have varied in brand and resin type.). Rustoleum seems to be replacing this with a '2X Ultra Coat' 'Painter's Touch' formula that is also good but not as smooth in the final dried finish as the older can, or so I believe. Again the name is strange since there's no "primer" in this formula and the "2X extra coverage" they promise is moot with clear since there's no pigment. They need a new marketing dept.

Not familiar with the Humbrol product but since it's water-based must be acrylic (I'd guess)and likewise would probably tend to be non-reactive with most dry/cured color coats as well as vinyl decals (stickers, transfers). One option I personally have not tried (but others may have) is commonly available in the US "Future" brand liquid "floor finish" from SCJohnson, I'm told this can be very smooth when sprayed and AFAIK is also acrylic liquid.
Do a trial application first!

one of Realsteel's many valuable how-to guides
https://www.bikeforums.net/18723504-post10.html

Realsteel's guides need to be collated in a list for future convenient access.

I've used plain old Rustoleum clearcoat over decals from pretty much all the internet decal suppliers with no problems. I find the gloss a bit too glossy but satin with a coat of wax over top looks good.

Double plus. That guy does some amazingly useful and interesting threads. ++

Are you sure? Sometimes you can get away without clear, if the decals (stickers) are stout enough.
A sign maker's edge sealing pen may be all you need. Unless looking for maximum durability.

https://www.sealitpen.com

Rootboy -- I guess I'm not sure. These came from H. Lloyd, and on the list I ordered them from, it said they were waterslide. They arrived, and are "peel and stick," then it says "peel, stick and remove cover," and then "Applied using full instructions supplied." But there are no further instructions included. Reading their definitions, I believe they are probably Vinyl cut, and it doesn't say specifically to clear coat them, but in a previous paragraph, it says that most decals should be. Maybe the sealing pen would be the way to go.

+1, first ever rattle can job that I thought looked better than OK and in fact great.

Interesting. I know Lloyd's does do some water slides, but not many anymore.
Unfortunate that they weren't more clear on the instructions.
Do they have a backing paper/film? That when you remove the slick paper film to expose the sticky part, then use the backing paper with decals attached, sticky side out, to position and lay down the decals?

Maybe an email to Lloyd's for a little clarification is in order.

As far as clear coating goes, if they are very thin, it's probably a good idea. Though rattle can would be the most economical way to go, I find them hard to control on something like a small, rounded bike tube. Lots of paint output, at fairly high pressure. So you may have to spray the whole frame to get things to look right. And there is a danger of over spray, etc. Which you can always work down with water and 2500 grit paper, or similar.

An airbrush is a neat thing to have, but requires somewhat of a learning curve. But you have so much more control, with output and pressure, etc. Might not be a justifiable purchase for one project.
Keep in mind, cheap air brushes are just that. If you buy one, make sure it is the kind that will accept the use of solvent based paints. Some are made for water based media and solvents will eat the seals inside. Good ones are not cheap, but I've heard good things about those Testors Aztek air brushes. And they fairly reasonable.

I tried their 2k Primer on my last Rattle can job. And it turned out to be the toughest (hardest wearing) paint job I have ever done.

Back in Feb 05, I got a NOS Titan frame from the 80's that had very thin, fragile paint over chrome. Very pretty, but some paint had already dropped off in a few small spots. I did the whole frame with the old Rustoleum Clear and it has held up fairly well. The clear coat is chipped some, but the original paint & decals are still there.

My Torelli came clear coated over decals & frame from the factory. The Rustoleum on my Titan isn't as durable as the Italian stuff, but it has preserved the Titan's paint scheme pretty well. I have since successfully used Rustoleum clear to preserve old decals on other bikes and some of my old woodworking machines. Will take some pics & put them up later. Don

Thanks for your replies. Yes, Rootboy, it has clear paper on both sides of the letters -- I think I'm to pull off the first side to reveal the sticky part, then apply, and pull off the top sheet. I was just at Ace Hardware, looking at Rustoleum clear and Krylon clear. Both say they have acetone and tolulene in them. Is this okay with the vinyl? I may just go the cheap route. This is my first attempt at replacing decals on a bike, and I am just wanting the name to be readable, I know it won't look perfect.

I got great results on two paint jobs with this product. It's nasty stuff though. A VOC Respirator is required and I covered myself from head to toe as well.

As I wrote my results with Rustoleum clear "enamel" over several types of cured paint and over vinyl stickers was uneventful: no lifting or wrinkling.
I don't use Krylon (except HAVE used Krystal Kleer acrylic sprays from Krylon and don't think the finish is either durable or smooth).
WHEN IN DOUBT always test first, IF YOU CAN'T TEST you can sometimes get an otherwise bad formula to "play nice" with your delicate paint/decals by giving the surface a VERY LIGHT "dusting/misting coat" first and allow that to fully dry (harden) before GRADUALLY adding some more LIGHT coats and allow generous dry time between each. If you go slow and with luck you build enough protection layers that subsequent heavy coats won't penetrate and soften the goods. YRMV and practice pays dividends.

Reading through the FAQ, which you have done, I would think that the 'Vinyl cut' is reserved for the single colour decals: 'Very good for one-colour logos.'
If you have a multicolour decal then it is more likely to be a 'Vinyl print/cut': 'BUT vinyl is pre-printed with CMYK colours plus gold and silver as required. Again we only use expensive vinyl. Application method as vinyl cut, but these decals MUST be clearcoated as the inks are prone to degradation by solvents and abrasion.'
Also on the FAQ is 'I get MANY requests as to what might be the best product for this. I usually suggest either Humbrol spray polyeurethane (from model shops) or Plasticote spray varnish (B&Q or hardware store).'

If in doubt, contact Steve. I have found his replies to be quick and answered my questions.

My decals came with instructions (given to my frame painter) and I have some additional ones (the 1952 specific Reynolds 531 and a BLRC roundel) now on the way to me. I will check if they have the installation instructions.