You use isopropyl alcohol (IPA) in detailing to degrease paint, glass and hard surfaces quickly. The key moment is after polishing and just before wax, sealant or coating: it removes oils and polish residue so the new layer bonds properly. A pure IPA cleaner such as the D-CON IPA Isopropyl Alcohol Cleaner evaporates fast and leaves no residue or streaks.
Below you will read what to use IPA for, how strong to make the mix and how to degrease paint step by step. For more on ratios and mixing in general, see our guide dilution explained.
What is isopropyl alcohol used for on a car
IPA is a fast degreaser, not an all-purpose cleaner. In the workshop we use it for a handful of fixed jobs. The 99% D-CON version is made for degreasing and prepping, and according to the product information it is suitable for glass, paint, vinyl, metal and leather.
Use | Mix | Note |
|---|---|---|
Degreasing paint before coating | Lightly diluted with demineralised water up to undiluted | Follow your coating supplier's advice |
Removing polish residue | Lightly diluted with demineralised water | Panel by panel, then judge under a light |
Prep before wax or sealant | Lightly diluted | Oils gone, the protective layer bonds better |
Glass | Diluted with demineralised water | Buff dry with a clean microfibre cloth |
Adhesive residue | Undiluted | Dampen the cloth, let it work briefly and test on a small spot first |
Steering wheel and gear knob | Diluted | Dampen the cloth, do not spray the surface directly |
How strong should your IPA mix be
Sources disagree on this, and that makes sense: it depends on the paint, the coating and what you want to remove. Some detailers use a light mix of roughly 10 to 20 per cent IPA, others use nearly pure alcohol. Those are rules of thumb from practice, not figures from the manufacturer. Undiluted evaporates fastest and leaves the least residue, but on a fresh or entry-level coating you are better off with a gentler mix.
For the D-CON IPA the guidance is: undiluted for strong degreasing, or diluted to your own judgement with demineralised water for lighter jobs. If in doubt, ask the supplier of your sealant or coating for their advice. Use demineralised water rather than tap water, because limescale leaves spots.
How to do it
Wash and dry first. IPA does not replace a wash. Remove dirt, tar and iron fallout first and degrease afterwards. On dirty paint you just rub the dirt around.
Make the mix. Pour the IPA or your mix into a clean spray bottle and write the ratio on the bottle. Tip: use demineralised water and give it a short shake.
Dampen the cloth. Spray onto a folded microfibre cloth, not straight onto the paint, and work one panel at a time. Wipe in straight lines with light pressure. Turn or replace the cloth as soon as it is dirty, otherwise you put the residue back.
Buff dry. Follow straight away with a second, dry cloth so nothing is left standing. Work in the shade on cool paint, then a mix that flashes off too fast will not leave marks.
Inspect. Check under an inspection light that swirls and scratches are really gone. Polishing oils can fill light defects for a while, so only after degreasing do you see the true result. More on polishing in polishing your car: removing swirls and scratches.
Protect straight away. Apply wax, sealant or coating as soon as the panel is dry. Bare paint left standing attracts dust and grease again. For how to lay a coating, read how to apply a ceramic coating yourself.
Work safely. Wear nitrile gloves, ventilate and keep IPA away from flames. Test on an inconspicuous spot first, especially on plastic, rubber or old paint.
Dedicated degreasers as an alternative to IPA
IPA is not the only product for degreasing paint. Depending on the job we also use:
Koch Chemie PPS Panel Preparation Spray: spray onto the panel and wipe off with a microfibre cloth. It removes dirt, grease, silicones and fingerprints. More in our guide to the PPS.
Menzerna Control Cleaner: made for the polishing workflow, to clear residue between steps. It wipes off streak-free, so you judge the real result.
Shiny Garage Scan Inspection Spray: removes oil and solvent residue so you can check the paint before sealing. Available in 5 litres.
Shiny Garage Pure Paint Cleaner: a degreaser without wax or fillers, for paint that needs to be ready for wax or sealant.
You will find all of them in the degreasers category. Want to lay a coating after degreasing? Have a look at paint coatings, for example Gtechniq Crystal Serum Light.
Common mistakes when degreasing with IPA
Using too strong a mix on a fresh coating. Choose a gentler mix and follow the coating supplier's advice.
Using tap water. Limescale stays behind as small spots.
Spraying straight onto the paint. You get droplets and streaks, and you waste product.
Keeping the same cloth. Swap it as soon as it feels dirty.
Waiting too long to protect. A bare panel quickly attracts dirt again.